I think a lot of people are scared by its price.
If you accept a BTC payment today, you could potentially lose 10/20% of its value in few hours.
The price of bitcoin is one valid reason why some people refused to accept bitcoin but if the price of bitcoin is high many people will prefer to accept it than fiat. For me, I will not refused because I know there will be a time that the price will increase and will help me to gain more money.