I'd say they should use ActivityPub[1] instead of wasting time on their own incompatible solution, but quite frankly I don't want Twitter federating with Mastodon. We get our fill of chuds with anime avatars thanks to Pleroma, and don't really need or want Twitter around because decentralization won't make it any less of a digital sacrifice zone[2].
For those unfamiliar with this situation: Pleroma is an ActivityPub server and frontend written in Elixir and designed for low resource consumption, somewhat of an alterative to Mastodon. One or two of the most prominent early Pleroma instances had very sparse moderation policies, leading some to associate Pleroma with trolls and far-right users. Today, most Pleroma instances prohibit hate speech, harassment, and so on. Of course, anyone is free to make their own Pleroma or Mastodon instance with whatever rules and federation policies they like, and the most "chud-filled" instance in the entire fediverse (Gab) is running a Mastodon fork, not Pleroma.
1: https://activitypub.rocks/
2: https://en.wikipedia.org/wiki/Sacrifice_zone