One of the reasons governments point out for not legalizing bitcoin is the fact that is prone to scam and not regulated. The  government will want to protect his citizens from anything not regulated and anything that's likely to be defraud from. You will agree with me that that's alot of scam activities going on with bitcoin, there alot of news going on with bitcoin scams everyday which the authorities are always aware of.
All these continue to happens, the government will still have reasons why they will not approve and legalize bitcoin. As they will always talk about the disadvantages aspect of cryptocurrency and neglect the greater benefits cryptocurrency brings.