Yes, LI 10-15 years ago was a decent site for professional networking, before it got too much like social media. Looking for work, get in touch with or keep in touch with people that you share professional interests with.

I guess it wouldn't be technically challenging to create a platform for this, the problem would be to bring the right users and as you say, moderate the content to avoid what it has become today.

Show your certificates? Amazing!

Selfie with some half-assed inspirational "leader" quote? No!