I wouldn't be surprised. Won't be an existential issue for Bitcoin though (beyond the temporary 2-5x price drop). Bitcoin doesn't need national approval to succeed. It will thrive in some jurisdictions and not in others.
Nation states have the most to lose, since they draw so much of their power from the ability to manipulate currency, so we should expect to see a lot of attacks on Bitcoin by them.
Nations can prevent their banking systems from interacting with exchanges. It should be easy enough to transfer value to citizens of restrictive countries regardless of the government's position; the trouble is the citizens' ability to transfer value out.
Your cousin Lenny had to get his BTC somewhere, with either an exchange or a mining rig in the path. States can make both of those paths very difficult - paying the exchange could require smuggling cash out of the country, and anomalous electric usages are already used to identify marijuana grow operations.
Nation states have the most to lose, since they draw so much of their power from the ability to manipulate currency, so we should expect to see a lot of attacks on Bitcoin by them.