The biggest concern with Bitcoin is currently ease-of-adoption and learning curve.
It takes years to really understand Bitcoin, at least for the average person.
Even learning how to buy it in the first place can be extremely hard.
Most people on this forum do not understand BTC (no matter if they owned it for years) because to do so requires a thorough understanding of global economics. What I see from most posters is that they understand the upside of speculation...but not much history of markets or what the masses accept or trust when it comes to buying or selling.
I can't argue with this. I am one of those people that have a semi understanding of bitcoin, but I think I'm learning more daily.