Replaced by whom?
I get that some people will step up into being Mods, but modding is hard and thankless work - I've done it a few times over the years.
There's always subs crying out for new Mods, so you'll end up scraping the barrel for Mods, then the quality will go down, people will get pissed off. With thousands of Subs suddenly needing modding, there's simply not enough volunteers to go around.
One of Reddits unsung resources was its army of Mods keeping the content of some quality (define that as you will). Reddit really is cutting its nose off right now.
Just subbed/posted