In my opinion there is nothing will change if ever bitcoin lose it's market dominance but it is impossible to happen. Yes,a lot of altcoins in the market that has a potential to grow but if you compare it to bitcoin it is too far from bitcoin that's why i believe bitcoin will still dominant over other coins in the market.
that is only for now. Bitcoin might become more dominant but might also decrease to only few % market in long run, at least that is my opinion. We can never be sure what happens