Unfortunately, countries are already starting to aggressively regulate the crypto market.
This means that they will use their fiat monopoly position to shut down any exchanges where citizens can turn fiat currency into cyrptocurrency.
That is the first step governments are taking in places like Ecuador and Bolivia. The 2nd step govs will take after that, is to patrol commerce and outlaw merchants from using alt currencies.
It's actually an interesting dilemma. The more governments regulate and tax cryptocurrencies, perhaps the stronger the market will become for completely anonymous currencies. Not much a country can do, though, if their gov bans crypto from merchants. In that case, it will become a store of wealth, rather than a tool of commerce.
Cryptocurrency & exchanges better start preparing now for an all-out ban, because it's already starting to happen. If Govs can't collect taxes, they'll start to take drastic measures, like India just did.