Bitcoin is the mother of Altcoin, perhaps that is a suitable word to describe Bitcoin's current position. After Segwit I hope its position can not be replaced with BTC split. As has happened to ETH split into ETC. Worth the wait for Bitcoin's future.
As we all know altcoin was made because many wants to follow the success of bitcoin and wondering if they will succeed too. Some altcoin copied or made platforms that are not far to bitcoin. As bitcoin is the top crypto currency and it will ever be. Nothing can change that even decades will pass.
They've just made that just to compete nor to have money to be converted on bitcoins and I don't see any coins can compete with it since bitcoins is most adopted coins around and people will surely go for it and make this as number one choice. But if you mean decades will pass maybe theirs some coin will gonna compete with bitcoins but they will face huge trials since bitcoins is 100% strong and establish.