Basically, the same systems that allow Skin gambling also allow for trading and 3rd party marketplaces. You can’t just disable one without disabling the other. They could ban it on paper but enforcing those bans technically will likely just lead to users/victums lossing more as casinos would be unable to payout owed earnings.

That leaves legal enforcement, but Valve isn’t a government body - they don’t have the authority to investigate these casinos, and have limitted ability to enforce the law. They’re effectively manufacturing poker chips and releasing them into an open market where they don’t have authority (nor should they). Instead, illegal casinos should be investigated and prosecuted by the government - its supposed to be their responsiblity to handle exactly this sort of thing. They have the ability to seize casino property to investigate them or collect information, and the ability to fine them and enforce fines, unlike Valve which can do neither. As even noted in the video, the have sent cease and desist letters in the past, but casinos can changed names, changed owners, ect. and nothing changed.

Disabling trading items is a bad call. Look at epic and rocket league. The game was already dying and removing trading was a massive fuck you to a huge section of the player base.