Coinmarketcap is not to be taken as a standard of quality. I mean Bitconnect used to be in the top 10 before it was exposed as a massive ponzi scheme.

https://coinmarketcap.com/historical/20171029/

Coinmarketcap just reflects what people invest in at a certain time, it doesn't mean that these investments are rational or are based on highly calculated decisions. A lot of coins in the top 100 are copycats, tokens or just concepts, very few are fully functional products.