All social media lives and dies by engagement. It doesn't matter if you're Lemmy, MySpace, or an obscure forum dedicated to ant husbandry, what keeps you alive is engagement from users. This generates revenue from ad sales and sponsored posts.
In my opinion the issue with LinkedIn is the duality of its use. Most users like you and I just create a page, upload our CV, connect with our coworkers and then close the app. We don't spend time engaged with the site, we're not moving a lot of traffic and we're not purchasing services.
So LinkedIn encourages "content creators" to try and bring in views, and then they try to sell things to these viewers. Want to be successful like this person? Buy LinkedIn learning! Want to have recruiters fighting over you? Buy LinkedIn Premium!
Generic content just brings in content and they bill it as career development.