most of them aren't really at fault. they are just poor newcomers who entered a big market and were suddenly bombarded by a huge wave of advertisement which were promising them riches beyond their wildest dreams so they ended up buying a ton of useless tokens which have been continuously losing value
While a lot of altcoins have been bad investments. Some have provided ROIs higher than Bitcoin!!
https://coinmarketcap.com/currencies/goldcoin/#markets