yes it may happen but i think bitcoin has reached to a level where it is difficult for any other cryptocurrency to replace it or reached to its level because it takes a huge time to evolve and bitcoin takes almost 10 year to reached this level. in other words we can say that it is the mother of all cryptocurrency.......
yeah bitcoin class is already very high compared to other cryptocurrency, in terms of popularity, the number of users, and so forth. bitcoin level is already very high. so it will be very difficult to be replaced by another cryptocurrency