About 2 million adults in the UK don't have government-issued photo ID. Certainly many 16-17 year olds will have trouble verifying their age. They're blocking huge sectors of the UK population from being able to use the internet normally.
Really they should just torch the lot.
Realistically, the kids will find their way around the ban.
Go and watch 3blue1brown and then tell me it's addictive cancer.
If you have self control you can avoid the social media element of it.
YouTube demonetisation tends to act as a reasonable steward on the platform, but it does need to be strengthened.
I.e. make YouTube responsible as the publisher for any video with over 100k views. This would be totally doable.