2/ Twitter is basically saying "hey the locks on your home aren't the most secure [true]... so we're just removing them at the end of the month [insane]"
Text message authentication isn't great.
And it needs to be evolved away from.
But this is reckless.
3/ You don't make users more secure by unilaterally *degrading* their security, then hoping they do better.
Security is a ratcheting process.
If Twitter goes ahead with this, they absolutely deserve regulatory & Congressional scrutiny.