No one is going to remove the crypto currencies,if we don't hold those cryptos they will eventually fade away that is the advantage of decentralization.
I don't think so. The useless altcoins are removed from trading stations with lack of trading by traders. The market decides which altcoin has potential and which ones are shitcoins. It depends on the analyze of general market traders.
Not all crap coins are being removed in the market. So long those "devs" are gaining money from their shit coins, they will create a fake pump of their coin or fake volume. But sooner or later, we will know the truth of this coin because when they get tired of doing those fake cycles of trading, it will soon slow down or die down.