You’ll have a hard time finding a jurisdiction where minors gambling (even behind the veil of “we don’t check who our customers are”) is legal. The “IRL item gambling” site in the video was in fact blatantly illegal in Denmark despite the lengths to which they went to pretend “it’s not gambling because the house always loses”.
Asking Valve to police gambling is the next best thing to do if governments won’t step in. You say it like it’s an impossibility, ignoring the fact that “state-run gambling” is quite a common setup. In France for instance all money games are run by la française des jeux, a state-owned monopoly whose profits are meant to go to charity. In the US it wouldn’t be a crazy idea either, given how many US states already have state-run monopolies for alcohol sales for example. It’s not like historical precedent is lacking to show that regulating a parasitic industry is possible…
Maybe you can find examples of other industries that are heavily infected with gambling bullshit, but that’s whataboutism and in no way relevant to the discussion.
Cease&desist every casino would be a good first step. Casinos are well outside the original intended purpose and if the ToS don’t prohibit their existence that can easily be changed. Valve doesn’t owe anyone the right to gamble their items, especially not with the weird third party escrow system that casinos use IIRC.
But if we’re touching on the subject then we need to reopen the contentious subject of the lootboxes themselves, which are gambling. Which Valve (and the video game industry) has an enormous stake in. To fix that whole mess, I expect a government crackdown will be required.