Say the original poster (OP) asks a terrible question so it gets closed. But others come by and see some value. So they edit to make it clear, focused, and on-topic. Does any of that matter if the OP can't be bothered to make any improvements themselves? Which is more important to the community, the actual current question or how it's OP has participated?
IMHO it should not really matter if an OP asks a good question, or if someone else takes a scetch of a mediocre question and edits it into something which deserves to be kept and answered. The idea of this site was always to create quality Q&A pairs, ideally helping a lot of people, not just the person who asked. For this goal it is important that not just answers have a high quality. Questions should have a certain quality, too, so other readers can easily understand what was meant and if the topic may be of help for them.
However, many bad questions here are so unclear, so broad or simply off-topic that without any support from the OP, one cannot easily improve the question without changing the meaning or the authors intent - which we obviously should avoid. For such questions, anyone here has to decide for themselves if
they think it is worth trying to ask the OP for clarification or asking them to make it on-topic (and give them some time to react)
make a guess about the meaning or intent, and (in case of having edit privileges) transform the question accordingly (which should be accompanied by a request to the OP to double check the edit, and/or an explanatory comment why this edit was necessary)
or just downvote / close vote for the question (if they think the question text has not enough substance to become the basis of a good question by some reasonable effort)
So yes, for terrible questions it is surely ok to demand effort from the OP, but it can be also ok to do not so, and if someone is willing to improve another person's question to make it focussed and on-topic, especially when the author does not react in time to any comments or downvotes, that is also ok - this is always a by-case decision.
Does any of that matter if the OP can't be bothered to make any improvements themselves?
It matters. If an O.P. doesn't bother to make improvements himself, then it's either a health vampire of a drive-by poster. In either case this is the kind of user I'll do better without.