The main reason why businesses and large corporate companies have not accepted Bitcoin, has to do with government regulations. A business cannot accept Bitcoin as "legal tender"... if their local government have not approved it.
So, this is the barrier that are placed by governments to protect their local currencies. The reason why they are protecting their local currencies are simple, because they have full control over it. (How much is printed... who owns it.... how much they own... how they spend it... etc..)

By far, the government is the biggest barrier to bitcoin's popularity. Not only businesses and companies do not accept bitcoin, but even people are afraid to use bitcoin because they do not want to break the law or resist the government. But honestly, it is difficult, if not impossible for bitcoin to become legal tender. Because as you said, through fiat they will still have full control over us, they can't use bitcoin to do that to us. That will happen if they figure out how to control bitcoin.