I don't think governments want to involve into this kind of market. The only thing that concerns them is how they get tax. The other thing, Will they accept it as a currency or as an asset? They seem to be quite confused about this.
There are still some issues as to how they would recognized it so that they can levy tax appropriately. For the exchanges, they don't need to create their own because they can just grant licenses to private companies and then tax them for it. The companies then would just require the users to have KYC and then apply tax to their transactions so that they would just accumulate the tax collected and they will be the one to remit it to the government.
I think it depends on the level of trust of the citizens towards their government. Why not issue licenses for already existing exchanges instead? The government shouldn't be engaging into business and the creation of an exchange would be a conflict of interest. They could generate revenue from that and that would be unfair for the market because they have control. That would monopolize the business of exchanges. It's not always best to have a government owned service provider, unlike what many people think. They can just tax the exchanges if they want to generate revenue.
This is what I have been saying. Instead of doing it themselves, they would just let the exchanges - existing or not yet - to take care of the business of trading and they would just collect taxes from it. Some people might not trust the exchanges if it's handled by the government especially if it has already an issue of graft and corruption.