The government can't tell an alcoholic they can't buy liquor or force a smoker to stop going three packs a day while having lung cancer.
They can't do that but they can fine a casino company £13 million for not adequatley vetting customers and seeing if they are responsibly gambling. Gacha at Phil's level is gambling in all but name, the reason that it's not regulated is that you technically always get "something" whereas there's a chance you walk away from a casino with nothing. But mentally getting anything other than the ultra rare pull is the same as losing.
I'm not saying it's right or wrong but idiots like Phil going bankrupt because they can't control themselves are going to be the reason MTX/Loot box/whatever implementation gets regulated sooner or later.