Fantastic video @craig-grant!
I must confess that I believe in other altcoins. No, I want say that they are better than these two, but from the investment point of the view I think that other altcoins have a great potential.
When you look at market capitalization, BTC and ETH dominance is huge. More than 60 to 70 percent. Other competitors will try to disrupt their position (by innovating and immitating) and probably one or couple of those will get closer to BTC and ETH.