We need whatsapp/telegram/signal to display a feed based on user's status and nothing more. It's almost free, frictionless and free from ads (for now). But sharing without the widest audience (just to the social graph of your contacts).
It could bring back Google+'s circles so you don't share the same stuff with colleagues and friends and family, but your feed page would display it all the same.
Decentralized micro blogging without the huge tech cost and barrier of entry of mastodon.
People could choose how people are allowed to react to their status: limited in time, to the latest status update, limited to emoji/thumbs up reactions, allows starting new chat with that status as a topic, etc.
It also reminds me of https://en.wikipedia.org/wiki/Pownce which I thought had some great ideas at the time.
There's no money in it though, so maybe bring back the old whatsapp model ? 1€ for 6 months or something ?
Or maybe just tell people to start a group chat in which they post updates ? Facebook/Twitter/Instagram got that easy to post/single tunnel thing simplified to the max, I don't think you can do better without being centralized.