I’m probably not the best person to answer because I blocked !memes but it seems like the latest trend is to post old school memes. It gives the older users a sense of nostalgia to a time in the early days if the internet. So I suspect a lot of people have focused on !antiquememesroadshow since it’s now a community.
Just like any internet trend, it will come and go quickly until the next fun and exciting thing takes its place.