You’d have to convince a lot of religious people to give up the day of rest they’ve considered a religious obligation for thousands of years.
Edit: I mean, we do now because of weekends. But the rest-and-worship day is supposed to be Sunday, not Saturday.
Precisely: Saturday is written in stone, yet Christians typically rest and worship on Sundays. If we changed that, why couldn’t we change the seven-day cadence? It’s not like the Church would object to more masses.