I don't know much about bitcoins, I know even less about altcoins. In few months, I see alt coins, and I think many others think like me judging by the comments, altcoins are there just for fun. Nobody takes them seriously, when I think about it, for many people who are not using bitcoins all this is a game, then altcoins are game in the game. There is no other explanation, so without altcoins bitcoin would be less interesting for many people.
And its nice to know that you can earn with some game, that is why everything with bitcoins looks so attractive.
However thanks for the belief with bitcoins and its potential Because bitcoin can normally exist without altcoins and would be fine since it's the original, it already existed without altcoins before litecoin was made, I don't think altcoins can exist without bitcoin. Hopefully You can switch with bitcoin itself to grow your money and for future investment.