Every day we get opinionated questions asked here. People seem to think that this is the place to ask them. New users point to the old open questions that have fallen through the cracks of time as reason that their question should be open too. Old Stack Overflow users continue to suggest reposting discussions on NotProgrammingRelated Programmers.SE. Consider this exchange on a Stack Overflow question:

This is not an appropriate question here because it is opinion-based. You might get help at Programmers. — Ed Cottrell (deleted)
@EdCottrell programmers has the same rules about opinion-based questions as SO. Please take a look at the help centre there before sending people our way. cheers. – MetaFight
@MetaFight my apologies. I see lots of these kinds of questions over there and didn't realize they weren't acceptable. – Ed Cottrell

We have been told in the past that when our site is full of crappy questions, our site sucks. Yes, the answers may be great - but the questions aren't. As said, fixing that is a painful process. It also means that we need to change the perception of what Programmers.SE is about. This means closing questions that are too broad, or primary opinion, or career advice from days of old.

Popularity of old questions does not mean that it is something that should be enshrined in a museum for all time. Well, thats what a historical lock is for.

This question exists because it has historical significance, but it is not considered a good, on-topic question for this site, so please do not use it as evidence that you can ask similar questions here. This question and its answers are frozen and cannot be changed.

(I will also point out that the new users who cite historical locked questions apparently don't read the text)

Programmers.SE one of the highest ratio of locked questions to questions of major sites (note also that the great contentious cleanup of SF hasn't been completely resolved). Digging into data.SE (feel free to refine the query - comparing it to search here, I do see discrepancies, however it is consistently applied to other sites):

Site | Questions  | Locked
P.SE |     37,017 |  744 (2.01%)
SO   | 10,258,635 | 2702 (0.02%)
Math |    496,668 |  638 (0.13%)
SU   |    284,455 |  764 (0.26%)
SF   |    205,689 | 4265 (2.07%)
AU   |    202,900 | 1233 (0.60%)
TeX  |     97,119 |  180 (0.18%)
U&L  |     74,315 |  220 (0.29%)

We are the most preservationist of the sites that are out there. We even tried moving some of our popular questions to the blog (it didn't work out well).

If you feel that it is necessary to reopen those closed questions of old popularity so that someone can add another answer and continue the discussion, then go right ahead. The site was down that road once before and we were told that this was something that wasn't sustainable.

In the meantime, the community that is here has defined our scope.

Programmers.SE is not Quora, or Reddit or any other site. We are a site to give practical answers to questions of software design and architecture. It says so right in our tour:

Ask about:
✔︎ software requirements
✔︎ software architecture and design
✔︎ algorithms and data structures
✔︎ development methodologies and processes
✔︎ software engineering management
✔︎ quality assurance and testing
✔︎ software licensing

Don't ask about...
𐄂 general workplace issues, career advice, job hunting, salary, or compensation
𐄂 implementation issues and coding tools
𐄂 what you should learn next
𐄂 what projects to do or books to read
𐄂 where to find libraries, tools, resources, or other product/service recommendations
𐄂 personal lifestyle or non-programming activities
𐄂 questions that are primarily opinion-based
𐄂 questions with too many possible answers or that would require an extremely long answer

As a Stack Exchange employee, reopening questions that are in direct conflict with what the site scope is about sends a confusing message to our users - both the ones asking questions and the ones closing them.

Yes, there are many wonderful blog posts in our old, off topic, too broad, and opinion answers. They may be worthwhile to try to preserve - as blog posts. It would be helpful to have people who are good editors to help us migrate these posts to a different medium and make posting blog posts something that is easier to do.

Referring to the specific question of http://programmers.stackexchange.com/questions/75486/why-arent-young-programmers-interested-in-mainframes when I started the close vote process on it wasn't its popularity - it was the tag junior-programmer that is littered with bad questions and itself being on the verge of a meta-tag. When looking through a tag, I tend to start at the oldest as those are the ones that have the most answers and the least fixable. This often means seeing some of the old popular ones before the newer less popular ones. However, the phrasing of:

Closing questions with great content years after the fact simply because they became popular seems like an inherently spiteful and self destructive way to make a point. You can certainly control your own scope, but when groups of users go out explicitly to hunt down the most-popular questions specifically because they are popular doesn't make the site any better.

is incorrect about my motives and needlessly antagonistic. It also suggests that you have a different vision of what types of questions should be asked on Programmers.SE. If this is the case, then please state it clearly. We've gone through this in the past and there is even a blog post that I am sure you are familiar with. In it, it states:

Thus, questions that are not answerable -- discussions, debates, opinions -- should be closed as subjective.

The question asked in the post http://programmers.stackexchange.com/questions/75486/why-arent-young-programmers-interested-in-mainframes falls exactly into that category:

Why is this? What makes mainframes unattractive to young programmers?

It is not answerable. It is subjective and requires extended discussion. It would be something to ask on a discussion board. The explicit question presented in the post is a poll of personal experiences. It is entirely composed of opinions and personal anecdotes. It is not within the scope of the site today. With its 26 answers, it speaks exactly to the first part of the blog post:

Most forums and chat rooms have a scale problem. As in, they don't. The more people that join the discussion, the more noise each of those connections bring. So the forums get progressively noisier and noisier, and suddenly one day … you stop learning.

Because we believe so deeply in learning, we are willing to go to great lengths to suppress the discussion, debate, and opinions that -- while plenty entertaining -- cause most forums to inevitably break down.

^{Note: as of this writing, your blog entry has a broken link, the correct link is provided above}

These old, popular, and off topic / too broad / opinion polls are ones that new users often find when they first hit the site and seek to contribute. This is unfortunate because they are often not adding anything that isn't there in the previous twenty some-odd questions, lack good writing skills, and are unfamiliar with the scope of the site. All of this leads to a rather negative experience for new users (doubly so if they ask another question like it).

Allowing these old questions to remain open is in direct conflict with providing new users to the site a good experience - answering a good question or asking a good question.