Fuck off Valve.

They won't. And then the glorious age of monetized mods will be ushered in.

Some random thoughts I want to share on this.

It occurs to me there could be a positive (or neutral, rather) to implementing something of the sort. Hear me out with a specific case: SWTOR. Now, SWTOR has the Cartel Market, basically a shop where you spend Cartel Coins to buy armours, weapons, decorations, mounts, etc. How do you earn CCs? It varies. If you're a subscriber, you receive a monthly "allowance" of 500 CCs. If you have a security key, you get an additional 100 CCs. Ingame, however, there are some achievements that can reward you with CCs but these are few and the rewards are paltry in comparison to the CM prices. However, SWTOR also has the Galactic Trade Network, more commonly known as GTN. More often than not, everything you can buy from the CM you can find in the GTN. You buy from the GTN with credits you earn ingame at a far more generous rate than the CCs. The GTN is also (as far as we know) self-regulated, meaning prices vary according to supply and demand (though there's always the guy who thinks he'll someday sell a black/black dye for 5 million credits).

So, to the point. I would not be against having the CM on an outside platform. In other words, it would be nice to be able to check on the CM from a web browser or from Origin itself. One could, potentially, extend this to the GTN as well. The key differences to note here, however, are: there's an already-established market economy inside the game; and you can buy these items through ingame credit without having to spend a dime (and I mean this is actually feasible, and not the if-you-do-1000-quests-you-can-buy-a-single-item kind of feasible). So, yeah, having this model available outside the game as well as inside is, in essence, harmless. It could potentially be even positive if modders are allowed to create items that fans are likely to crave and devs are just as likely never to release like, dunno, Vader's armour (though modders wouldn't get paid by customers since they spend ingame credits so they'd have to be paid actual money by the devs). By making this service available outside the game, and provided you have a platform that allows you to create these items, you're basically outsourcing content development at a fraction of the cost and probably increasing revenue.

Unfortunately, the model Steam seems to be encouraging is one paid with actual money as opposed to ingame currency. I don't particularly like nor support that. This system could easily encourage developers (or publishers to pressure developers) to create less content for the core game and then create items to be sold piecemeal. The worst part is we might not even realize it's happening, especially in the case of a new game/franchise. After all, who defines what the "core game" is? Imagine if BioWare had sold you decorations for Skyhold as items? (incidentally, they did something similar with the Spoils packs) Worse, imagine if they'd done that for Dragon Age 2 (incidentally, they also did that but with armours/weapons), a game with environments so bare-bones you might have been prone to do some decorating out of pity.

It does look as if Steam is trying to find a workaround to persuade people into buying "items" so later they can go back to selling full-blown mods.

Didn't know were to put it

How can you stretch "some people made fun of me on Twitter so I got my media friends to demonize their entire hobby" into a 2 hour Hollywood movie?

How did they get 2 hours from Paranormal Activity?

Starring Lexi Belle.... LOL.