What's missing is that other platforms, like Facebook, took a very hard stance on this and forced people to signup as their real identities.
Twitter, can easily follow suit. That won't fix all of the problems, but it will go towards improving things and it won't require massive product updates and changes to the UX.
Given that their MAU growth numbers are low, and no longer the number that they want the public market to focus on, actually instating this now wouldn't even be that damaging from a reporting perspective, and if they bled out a few users that weren't really contributing it could go a long way to improving things.
Technically there is a privacy setting that twitter doesn't play up that can be used for people that want to use twitter as a consumption platform and limit the interactivity from other people.
Twitter is still fundamentally different and more open than facebook and with requesting non-anonymous users they can still keep that open platform and potentially clean up some of the outlier conversations that seem to be a focus for so many people of what's wrong with twitter.