Kids aren't going to pay for a VPN, even if they had the option to. They're going to Google "Free VPN" and download the first option which will probably add their device into a "UK residential proxy" botnet. Everyone is getting something out of it, the state of UK cybersecurity is weakened further, and no money is changing hands, good luck stopping that.

It's the same thing that happens every time the government tries to ban something that customers actually want. You get a black market, criminals make more money than ever and use it to fund other crimes and the banned thing continues to be available but now the suppliers don't have to follow other laws because then the customers can't object when they're both doing something illegal.

Governments never seem to learn.