Title says it all.
There used to be several tens of thousand on servers like minecade, mineplex etc, now there are only about 1k on good days on minecade. And you should consider yourself lucky if you find a modded server with over 20 people on at once. One year ago, modded servers had 50-200 on at once sometimes, and where very well developed and had good staff. Now, there are barely any that aren't 0/max and normal minecraft servers are usually only 100-250 for the average non minigame server. Is this going to continue?