The question was not closed for being off topic - it was closed for being not focussed enough.
Askers on this site are expected to do some research on their own, show us what they found and why it did not suit their needs. You will find a detailed explanation in the older meta post "Why is research important?". If questions don't follow this advice, they are often closed either with the predefined "needs more details for clarity" reason, or the predefined "needs more focus" reason.
In the question in stake,
Elasticsearch is a product (AFAIK with a freely available core), which can be used to build a search engine for ones own data
Google and Bing are services for which I assume I do not have to explain them to anyone here.
In reality, the distinction is not that sharp, the company (Elastic) behind Elasticsearch also offers service for companies, and Google and Microsoft also offer competing products/services for companies which may be used for comparable requirements.
IMHO the question text does not make clear whether these differences are understood, or if the problem is somewhere else. Maybe you want to know if Google or Bing are using similar software or algorithms, or maybe if they are using Elasticsearch itself for offering their services? This is something we cannot really answer here, because such internals are often company secrets (and we do give speculative answers about third party products on this site).
So I am not sure if an attempt to make this question more focussed can bring it into a form where it would be accepted as on-topic - currently, I have my doubts this will be possible. But maybe what I wrote above already answers your question, or at least gives you a pointer into the direction where you should look by yourself?