90% of classic players have no clue what a playerworld is and if they have they probally don't even know how to acess servers off of the list.
It should be advertised and updated as alot of tools are outdated, client still says you need to pay for a gold subscription which confuses newer players.
As for servers many aren't given much motivation to keep on going as client is dead and the chances of going to mobile are 1 in a million plus there is the fact that it takes forever to get approved for such things.
I would blame the death of unholy nations and zodiac for the current state of client as they were the most popular servers and we are now at a huge loss of players.
developers attempt to work on newer servers nowadyas but they never last that long
in general its just management issues and the lack of care given to pc client.