This problem probably can't be solved entirely technologically, but technology can definitely be a part of solving it. I'm sure it's possible to make parental controls that most kids can't bypass, because companies can make DRM that most adults can't bypass.
This is exactly what I meant by my above comment: It’s like the pro-ID check commenters have become completely disconnected from how young people work.
Someone’s 18 year old sibling isn’t going to be stopped by “should know better”. They probably disagree with the law on principal and think it’s dumb, so they’re just helping out.
But imagine if a locked device was treated like alcohol. Most kids get access to alcohol at some point despite it being illegal, often from older siblings, and rarely with legal consequences for the adult. But it's much less of an issue, because most kids don't get it consistently. Furthermore, "good" kids understand that it's bad, and even some "bad" kids understand that they must limit themselves.
Since people are already talking about using the law instead of parenting this needs clarification. Are the parents the one that would revoke their privileges or the government?
Exactly the same way that kids used in former days to get cigarettes or alcohol: simply ask a friend or a sibling.
By the way: the owners of the "well-known" beverage shops made their own rules, which were in some sense more strict, but in other ways less strict than the laws:
For example some small shop in Germany sold beverages with little alcohol to basically everybody who did not look suspicious, but was insanely strict on selling cigarettes: even if the buyer was sufficiently old (which was in doubt strictly checked), the owner made serious attempts to refuse selling cigarettes if he had the slightest suspicion that the cigarettes were actually bought for some younger person. In other words: if you attempted to buy cigarettes, you were treated like a suspect if the owner knew that you had younger friends (and the owner knew this very well).
Digital ID with binary assertion in the device is an API call that Apple's app store curation can ensure is called on app launch or switch. Just checking on launch or focus resolves that problem. It's no longer the account being verified per se, it's the account and the use.
(So you need to keep all your stuff into one device to be fully tracked easily. And have no control over your device, share your location… )
If we must have controls, I hope the process of circumventing them continues to teach skills that are useful for other things.