Well, I would love to know what has been more important for the many years that Evernote has been developed. As has been pointed out endless times, this is an extremely basic feature. Actually two:
Find/replace within a note.
Find/replace across notes.
Both are useful. Though I would prioritize them as listed. As someone outside the company I don't like to speculate unless I can point at some evidence. So in my opinion it is just as likely that they:
Have much more important things to do (that aren't evident).
Don't listen to their customers.
Are in maintenance mode and are just keeping the lights on for as long as possible. That means focus on "must haves" like platform updates, devops, etc.
Unless Evernote staff comments we don't have any idea. Frankly I am going to spend some time with bear and see if it is a suitable replacement. If Evernote is in maintenance mode, it is time to move on. If they just don't listen to their customers, it is time to move on.