Making a new Twitter isn't that hard to do. E.g. here is an article about a decade+ old paper on handling the challenges of doing so. To overly simplify, the hard parts are a) getting a large enough audience to adopt your new thing, which is necessary to overcome Twitter's current ubiquity, and will be hard unless you catch on in a very viral way, and b) handling the scaling issues if you do catch on at that level. c) is probably how to make money off of it, which Twitter still struggles a bit to do.

It's possible Jimmy Wales could be a big enough name to get people to use a new rival, but I have some doubts there. You really need something that catches the zeitgeist of this moment, and as other people have said in this thread, I'm skeptical that another Twitter could do that; what comes next will be something new.