Even after quite a lot of pump and dump experiences, exit scams, shitcoins and the rest, investors still time and again fall for the possibility of altcoins to make them rich, the thing is users who choose many altcoins and randomly invest in them are just basically looking to "get rich quick" through crypto, some of them hardly even do the tiniest bit of research on what they are putting their funds into, they just go in like it's a "lottery" and hope it can produce ROI in some time. Having said that I wouldn't even tell users to chose from coins within a certain amount or from the top or bottom of cmc, if you're a long term investor, then what you need it a coin that's sustainable for the long period, and it's Bitcoin, if you want to invest only shortly, then you can look in the direction of some of these altcoins and hope your money doesn't 'go away'.