In the UK parents can give children alcohol below the age of 18. parents get to make the final decision at home so I do not think its really comparable.

I would personally favour allowing parents to buy drinks for children below the current limits (18 without a meal, 16 for wine, beer and cider with a meal).

The alternative to this is empowering parents by regulating SIM cards (child safe cards already exist) and allowing parents to control internet connectivity either through the ISP or at the router - far better than regulating general purpose devices. The devices come with sensible defaults that parents can change.