what it really boils down to is numbers. In order for Twitter to deal with abuse on it’s platform in any kind of realistic manner they would need to spin up a whole division of dedicated abuse support people.
There are that many users of Twitter and that much abuse on the platform. This not only cuts into their bottom line, it also conceivably opens up a pandoras box of new questions. Can corporations file a claim that they are being trolled if people hold their feet to the fire on twitter?
Sadly I feel that we have crossed some tipping point where we have lost any hope for civility online.