This will tend to suggest that the problem you think bitcoin will eventually face has not come up yet, right? if that is ever the case, then i doubt one can think of any of such issue that we can not see at the moment.

bitcoin is not a perfect invention that is void of challenges and so far, the issue of attempt to regulate it has been at the forefront and will continue to be a major challenge because as adoption increase, institutions and firms will make attempt to regulate it or at least dictate what becomes of it. the internet still has a lot of limitation but yet, because of it other advantages, users have learned to cope with it and it relevance still stands even in the future. you do not expect resistance from known an unknown sources but bitcoin will still thrive amidst such resistance.