Well bitcoin doesn't have to be the crypto of the future. Sure it will go down in history as the father of crypto and the bearer of blockchain's early years but it's inevitable that somewhere along the way, probably in the future, there will be alts that can further push this market forward.
Altcoins will always be secondary to bitcoin. Considering the purchasing power using different crypto for other crypto the biggest orders are always in either fiat or btc and sometimes eth. There is always the market and the demand for altcoins to grow but they will not become bitcoin 2.0 because there does not exist and will not exist anything that is like that.
I would say because Bitcoin and Ethereum both have the blessings of not being securities by the US government. That's a massive deal that won't be allow something else to knock it off easily. That and the whole Satoshi thing keeps a leader out of it and all humans has issues and faults which we get to avoid.
Perks for those who are in the first world countries. Glad we are not in the same situation because in future who knows SEC might want want to jump onto cryptos as well.