Because they have nothing to test. It doesn't exist for people to just play on or test their ideas. It's for testing new things to the game.
test servers should open, I got to the game after a long time, there are dozens of things I want to test, plus I assume there are tons of players who want to test new events.
Years later we come to the game and we can't test anything, then there is no reason why the 54-person team should come back to the game with me.