To be fair, there are already apps that require a mobile phone to sign up, for example, VK, Telegram. And I think Google requires to scan a QR code to register account, so it is easier just to buy a Google account on a black market if you need it for some purpose.

Nobody trusts web browsers nowadays.

I think you and I move in very different social circles...

I would have no idea how, nor desire to purchase a Google account on the black market, and I do in fact still trust that my web browser can do TLS correctly.