No, they haven’t been trying to solve the problem. They want the bots on there for financial and political reasons. It is easy to solve the problem - require identification to use the site. I mentioned the advantages of social media doing this about 10 years ago and was downvoted on this very website because of “privacy and anonymity on the internet is great!”.
Just to note, there are many reasons to not want to "require identification to use the site" that aren't related to "[wanting] bots on there". Cost, friction, safety/protection, etc. - the list gets quite long with a trivial brainstorm.
Also note: that's not the same thing as saying "Twitter shouldn't require identification to register" (though personally I don't think that it should). It's just to say that it's WAY more complicated than "bots vs. ID".
I do think that would work but I think twitter probably could detect bot actions if they wanted to in a more nuanced way. Swarms of new accounts making similar comments has to be detectable on their end.
