Yes, development decisions are driven by user interest. WYSIWYG was prioritized, for instance, because of a long ago poll on the Discord and, well, it is the most popular request of all time:
Filter and sort the forum feature requests for popularity by selecting a category and then choosing your time frame and sorting options. Here’s all Feature requests sorted by popularity:
Of course, popularity isn’t the only factor. Ease of implementation is a major consideration. For example, multiple windows is currently very difficult because of Electron’s fundamental engineering.
Then there are other factors: the devs’ designerly perspective; sometimes features are developed with other features also in development that work together; FR velocity (e.g., a lot of attention on a FR in rapid time); whether there are good alternatives or workarounds for the need; and so on. (I’m not speaking for the devs, here, by the way. This is just what I’ve observed in software development.)
But yes, the Feature requests category is a major driver of development direction. That’s why we ask users to please follow instructions carefully when submitting a new idea.
As for swamped… well, there are currently 2,600 Feature requests. (779 #feature-request-archive isn’t so bad, though.)