One of the biggest factors that keep Bitcoin alive is the development team behind it. What if this developer team breaks down? Are there any other people who can continue the project in technical terms?
as you may know bitcoin source is open and anybody with c++ and programming knowledge and also knowledge of bitcoin protocol can learn and develop it.
there may not be as many people who fully understand the bitcoin protocol but since there isn't only one person developing and also because there are others who have the knowledge it is never going to be a problem to pass the torch to other people.
that is why there are so many altcoins, anybody with little knowledge about these things can copy the code and make a new one.