.Just because coin X was forked from coin Y and coin X may be better, the "markets" would disagree. The more options that are out there to make money off of the better they are. Hence part of the reason there was such an influx of alt coins a year or two ago.
Cheap money and greed, thats one of the major factors of why coins still exist. In addition to that, there are other factors such as a coins notoriety. Bitcoin arguably is behind the curve in terms of technology, yet its much more well known therefore people are attracted to it more.
Also I will add that even though I am heavily involved in Litecoin, I support Bitcoin and many other alts. Although I personally know little about Bytecoin and Monero.
