The same thing with blogs in general. A post could be popular and ranked highly in 2020 but in 2025 it's not even ranked on a search engine, even if the content is still highly relevant and fully working. It's bad because you could have a 10+ year old site with 500+ posts but nothing old ranks anymore, there's no ranking bonus on new stuff from having a snowball effect of previously highly ranked stuff in the same category.
Sites like StackOverflow sometimes show old things from 2017 because there's a bunch of recent comments. For a blog, even if you change the "updated at" date to something new, it doesn't matter and rewriting the post with different words makes no sense because the original content is still accurate.
> If your courses on Udemy aren't seeing the traffic they deserve, close your account, and create a new one... assuming that's feasible and they don't check too hard
Creating a separate account likely wouldn't work, at least not in the US. To get paid you have to fill out tax forms which has your social security number and other personal info tied to you as 1 human.