To be honest I suspect they wanted to do this before, but the power mods wouldn't allow it. I definitely remember the staff posting a proposal to allow second chances for closed questions, and it was downvoted to hell by the mods. They presumably got scared because they were getting a lot of free labour from the mods (even if it probably wasn't exactly the kind they wanted).
Now StackOverflow is dead the mods have no power, so they are free to make changes.
Typescript projects are a significant effort to set up with the traditional tooling (NPM & Node). With Deno you can literally just create a
.tsfile and run it.