I'm not sure I buy this. The API meant they effectively outsourced product development instead of developing that competency internally. It's no surprise that the company struggled to develop compelling features or products for years (both before and after closing the API).

Instead of no longer paying attention, just manage your timeline better. Stop following people who automate tweets, it's mostly garbage and it comes with extra baggage like more click-tracking and redirects. I've found that most of the items people share on Buffer are things I already read here on HN or saw someone else share earlier.

Not following too many people is great, because the people you follow will curate the interesting stuff for you and re-tweet it. Stop following all media accounts for instance, maybe follow a couple reporters instead and you'll still catch all the interesting stories.

If un-following is socially awkward for whatever reason, mute people you follow or at least toggle off re-tweets for those that do too many.

I read my whole timeline most every day and it's great. It does take regular pruning though, like a plant in your garden.