The problem isn't "2fa": the problem is services that just use it as your identity. You'll go to sign in to the account and it merely asks for your phone number, to which it sends a login link. Or--even more unacceptable as it makes you THINK the password matters--you'll say you "forgot your password" and it sends a code to your phone number and that code is all that was required to get back into the account. This isn't a second factor: this is replacing your first factor (your password); maybe you could call it an "alternative factor"?