All existing altcoins will collapse sooner or later and they will be replaced by new cryptocurrencies.
Just don't say that Bitcoin is one of the altcoins. Bitcoin is Bitcoin, and all other currencies are alternative (alt) for Bitcoin coins (coin) = altcoin. So no altcoin can ever become the next Bitcoin.
Bitcoin is an idea and all altcoins are just trying to "improve" the idea.
Maybe sometime a new idea will appear that will be more interesting than Bitcoin and will be able to replace it. But at the moment there is not even a hint of creating something like this.