Back when communities hosted servers instead of companies, it seemed less common, even though it was easier to do.
With competitive matchmaking cheaters can hold players hostage until the end of the match, as leaving incurs penalties and cooldowns that temporarily ban you from playing.
If admins allow cheating - people that want to play would leave the server
If live in a non-metro area, you probably have a handful of server your latency allows you to play on - getting banned would be a big suck
Now you just click "play game" and you get match with some strangers you might never play ever again with. Financially, those privately hosted servers no longer make economical sense for game publishers.