In the future, everything can happen and even Bitcoin can be replaced with other coins. Ethereum and Ripple are very good coins and have enormous potential. But I don't think these two coins can replace Bitcoin. Even to get close to Bitcoin is very difficult.
It seems to me that Bitcoin holders can still make a good profit after a certain time, because there are certain hopes that Bitcoins fate will be decided in the coming years. In addition, it is likely that Bitcoin can be used as a means of payment, they are for making large transactions.