Yes there will be many cryptos and many Fiat currencies and all the other assets, but Bitcoin will reign supreme as store of value, the ones storing in other cryptos will be loosing against btc and be poorer. For spending it's a bit indifferent what you choose, but as more people realize btc is the best savings tech they won't accept other cryptos bc they will likely have to swap to btc, and no one wants extra hops.