Not entirely - both Facebook and Twitter also show you "suggested" content and contacts and quoted/reposted content from people outside of your network. Social media algorithms are designed to maximize engagement and encourage adding to your social graph. OP seems to be suggesting a social network where algorithmic feeds don't even exist and all content is whitelisted.

I want to suggest federated social media like Mastodon, which is pretty close but it still has boosts and quote tweets, although you can turn them off in your settings.