> I would pay $100/mo for it.

For a good quality one? Same. Signed up.

> In a lot of countries, "everyone" uses a single platform and it's not a big deal.

> As a US user of 5 apps, some for business, it's just a mess and a constant source of friction.

Depends on what countries you have in mind, but it's pretty much the same elsewhere. Messenger, Instagram DMs, WhatsApp, Snapchat, Viber, Discord, Telegram, Signal... You just need to have all of them and this seems like a very elegant solution for having all your messages in one place.

Agreed. I would kill to not have to use Snapchat's app to talk to some of my friend groups. Same goes for Instagram.