I can't imagine it's that hard when there's still 30 teams and four levels. But it's probably not a product that needs to be nine innings. They also play the Celebrity Softball game (same ticket, five innings).
When I had season tickets to Round Rock in its AA years the All-Star Game, which included all the leagues and still divided teams by AL vs. NL, was really fun. I guess the AAA game survived a lot longer (until COVID). I imagine the players are happier getting the break (and probably didn't get paid that well to appear in it).