If you follow someone you're still more likely to see their posts. You just see other stuff too in the "For You". It's algorithmic, and at times annoying - but contrary to the article is still very valuable in my experience.

I would say twitter stays about 1.5 months ahead of every other site I know of on AI news in particular. I've usually had time to demo new tools for quite a while before hearing about them on HN or elsewhere.