It's pretty trivial to make Bitcoin virtually useless. Pass some laws that effectively render it useless to corporate entities and it's basically banished to the shadow realm. Won't stop criminals from using it, but you can regulate crypto to hell for 99% of the population.
The law fighting internet stuff seems very difficult. Just look at the rich media companies. Name me a movie or song and I'll download it. Even with all their money and laws they couldn't stop this. So how would you expect them to stop internet money.
The government cannot make bitcoin worthless through legislation. The government can make bitcoin worthless through an attack that costs less than 1% of the DoD budget though.
What do people use Bitcoin for? Buying drugs online! If the demand for drugs is inelastic, then presumably the demand for a way to buy them online is somewhat inelastic too?