In the present situation it is not possible to cross the bitcoin because bitcoin is already well established and it impossible. Already the prices very low and establishment of technology increasing.
bitcoin can never be replaced by ethereum or ripple, in my opinion,
bitcoin will remain number one in the world of crypto currencies
You can not tell exactly the future because the story of the future is always a mystery to everyone, especially about a field where volatile values such as cryptocurrency, an accurate prediction is impossible. Although now bitcoin is still a bright star and repels all rivals like ripple or eth but in the future, sometimes the ripple or eth receives an overwhelming support and begins to resist, turn around and replace the bitcoin, this is still possible.