Personally, I really like forums and I grew up with them. It takes some time to get into a forum though and understand how it's structured. TikTok, Instagram, etc. are easier in that you can just start swiping/scrolling. I have friends who don't understand how Reddit or forums work because they are a bit harder to use than just to open an app and start swiping. You need to understand the different subforums, etc.
Not saying it can't be done, but there are easier alternatives now. I think a lot of young people (my age or younger) just don't bother with the old, more complicated stuff.