Many reason why a lots of people accessed and used bitcoin, actually it is a business that has proven and tasted of being an instruments of making money. However if price of bitcoin become stable, the answer is only a form of speculations, because no one can prove that bitcoin price in the future become stable. If we based for the past years of bitcoin operations, not even once that bitcoin price become stable.
Getting a stable market value is very much impossible for bitcoin to have as it is more or less having a volatile nature as the market price keeps on changing most of the time. However, in case this thing ever happens, then there will be likely chances that most of the investors will stop investing or buying more coins as it will exactly be the case which has happened with gold few years ago.