Difficult to project in the long term but for now and probably short-term, bitcoin coin can't be dethroned as I see even additional value added to it
Through these years bitcoin remains the King of Crypto Market. People thinks for the past years that it can beat by other coins but until today it is still on top amongst other coins. It cannot beat indeed and hopefully we will see a good future ahead in bitcoin.
I don't know why it's difficult to project when we already have 10 years of history to Bitcoin, and at best 4 years for a non big alt, in this 10 years we saw adoption and use for Bitcoin rise so high. Alts struggle to get that kind of adoption unless they're old or they're so big and can spend a lot of money in marketing.
Long term for sure Bitcoin is still dominant, maybe 50 years is a different picture but 10 years? Same story.