Since blockchains do not die, I think altcoins have a future, but I can say that in the long run the chances of having a good financial return through Bitcoin are much greater.
Some alts may give you 3x, 5x or even 10x in the short term, but in the long run Bitcoin can be a much more rewarding investment.
Blockchains can fork to death if they're not maintained properly. A community could chose to pick a fork up again, sure, but that would be too much baggage.