However if nobody asks questions, there will be nothing for the experts to answer. And it is a fact that other Q&A sites exist.
As someone who has a question, there are several metrics you will take into account when considering where to ask. First, how much effort is it to ask a question, second, what is the chance that you’ll get a good answer (note that it is not always the experts who give the best answers; sometimes, what is needed is not so much expert knowledge as didactic ability — an expert may know more things about topological spaces, but for easy questions, someone who has just successfully finished a topology course but has excellent didactic ability may be much better qualified to answer).
If you scare too many experts away, you lower the chance to get a good answer. But on the other hand, if you raise the bar on asking a question too much, people will simply go to another place where it is easier to ask. There’s a sweet spot where enough experts (not all of them!) feel comfortable, and at the same time enough new users (again, not all of them) feel the effort worth the results.
Focusing too much on making experts feel well will kill a site just as thoroughly as focusing too much on making newcomers feel well. SE currently is biased too much to pleasing newcomers. But I have the impression that you are biased too much at pleasing experts.
Both newcomers and experts matter, and the goal of the site must be to balance out their needs as much as possible. That inevitably means that some users will not feel welcome (and there’s nothing wrong with it), and just as inevitably it will mean that some experts will not feel comfortable (and there’s nothing wrong with that, either).
Not only users asking bad questions are detrimental to the site, also experts holding new users to unreasonably high standards are.