I dont know if you can buy all just one crptocoin and pump it like usual then sell it like it just piece of cake here. Lets say that you can buy all of the X coin then you need to attract people to pump it too follow your stream. If not you will lose this thing and you can't get any profit from it
There are these kinds of pump every day for some coins. But the rise is not sustainable, as it is just a pump and dump. There is intrinsic value of the coins. These coins are just for pump and dump, there is no active development of the coin. There are many people fall into victim.
But I dont think there is much pump of alt coin because you need to choose wisely which one good for pumped. Because the volume of alt coin is very slow up and down just a little raise only except there are big whale pump that altcoin so you will earn it