As a store of value, I see bitcoin maintaining it's dominance. The way I see it, if 1% of the population has heard of bitcoin, 1% of those people have heard of ethereum, and maybe 50% of that 1% have heard of altcoins. Less even care to invest.
But as you stated, there is definitely technological value in the other coins. I think that there can be a world were many cryptos thrive with their own purposes. I fully believe in ethereum myself. great post.