I think VPN prosecution could happen if it was treated more like traffic offenses than like felonies.

Force ISPs to log all connections and make ISP customers accountable for their traffic, like they are in Germany for example. If you detect an IP to be used for a VPN, ask every ISP to disclose al customers who interacted with it and issue them a ticket. Three tickets and you're denied internet service for two years.

I think this would scare most people off.