This certainly is annoying. Many years ago when I first found Wikipedia, I would sometimes just type in my notes from some university classes. It was kind of a garbled mess, but every time it just took a couple days and someone had edited it, turning into a decent article.

These days even much higher quality content will be deleted. For something to be accepted now it needs to be like something written by a professional writer and follow all kinds of guidelines for style, citations and much more immediately. Nobody fixes issues anymore, if there's any issues or something is not very well written it will be deleted immediately.