If it's faux-gambling now, at what point does it start to fall under some sort of real gambling regulations? Doesn't the US at least regulate online poker and similar games?
You are about 5 years too late. Skin trading is already actual gambling, there are many sites that allow you to buy skins then gamble with them and cash out money. This isn't a hypothetical, it is a business model and I would be amazed if publishers were not aware of it.
Steam's market is also regularly used for actual money laundering through trades and inflated buy orders.
I was only superficially aware of that type of stuff (I play CS:GO every now and then) but not what skin trading actually was nor the money laundering aspect of it. Seems that if Valve wanted to do something about it, they would, right? e-sports are very popular now and they make you use their Steam phone app if you do want to trade something on the Community Market. I guess since it's not technically illegal and they get a cut of it, they don't mind looking the other way (or maybe don't think of it as a negative).
It's becoming quite obvious that Valve has very little interest in making their community in any way "good". Given how badly Steam Greenlight (and now Steam Direct) have gone -- with cheap (to produce, not to purchase) asset flips just dumped on the front page with no real vetting from Valve or the community -- I wouldn't put money on them even giving enough of a toss to notice that they're encouraging children to develop addictive tendencies via online gambling simulators. And if they have noticed it's "not their problem".
