This would require that, between now and 2021, it becomes possible to use HTML+CSS to create an exact publishable layout, and someone makes a TeX renderer that uses it. That would be great. I'm not optimistic about it, given that right now we can't even manage to standardize e-books, but yes, one can only hope.

(It's not that the TeX tuneup inherently needs to be formatted like a publication; but that's what TeX is for, and it would be silly to expect that the TeX tuneup would not be written in TeX.)