I don't think Altcoins will gain a higher market share than Bitcoin. Although Altcoin has many technologies and applications in practice. However, choosing altcoin to replace BTC is a long way. BTC alone has fought nearly 70% of market capitalization.
Bitcoin will always dominate the crypto market and even I have more bitcoin than other altcoins together in my wallet but we cannot deny the fact that altcoins have more features and new technologies which can be used in real world and altcoins beat bitcoin in terms of technologies and features so I think altcoin will be adopted more by start ups in the future but still altcoin cannot dominate crypto market.