if it were easy to manage 500/600 different altcoins, few exchanges would be enough to cover the whole market, and frankly it would be much more convenient
Yobit managing around that number , do you really think several Yobits would cover all the bases in crypto exchanges?
most of the lats are just useless copies of the same idea , it is hardly 100 coins in total worth to be considered no shitcoins
the rest is made to earn money for the creators and in most cases they are useless
but since the whole market is new , the Darwin's principle is not working as of yet