OK, I talked about the noise scene. Time to talk about the Sims scene.
The Sims games have at least as many players as D&D, almost certainly more: WotC claimed there were 1.5 million regular D&D players, while EA sold 20 million copies of The Sims 2 (but that doesn't tell us how many are regular players.) I didn't get The Sims 3 and don't do The Sims Social, so I can't really talk much about that scene, just the scene as it was when The Sims 2 was the hot thing.
There are multiple, huge Sims forums that dwarf RPG forums like RPGNet. Including forums for the Sims modding community, like Mod the Sims and More Awesome Than You. What the community calls "creative content" -- stuff made for the game by someone other than a Maxis/EA employee -- is mostly clothing, wall and floor coverings, all of which can be done with tools provided by EA. And of those people talented enough to mod objects, many only did "recolors", like beds or dressers taken from the game with minor color modifications. This feature became built in to The Sims 3, from what I've heard, but it had to be done with modding tools and distributed outside the EA forums for The Sims 2.
Now here's where it gets tricky: some people wanted to be paid for their efforts. Technically, selling third-party content for The Sims 2 goes against the game's EULA, but since some modding and artistic creation take a lot of work and talent, you could see how some people might want compensation. But the recolors? Sure, there's some monotonous work involved, but not much artistic talent is required, and all the technical talent was provided by the people who wrote the recolor package and modding tools, or who figured out the recolor steps and wrote a tutorial.
Yet, there were people who either tried to sell recolors or who distributed them for free with a "licence" that said "DO NOT USE MY OBJECT FOR MODDING!" As if they were maintaining some kind of artistic integrity. And yes, there were huge debates (flame wars) across multiple Sims forums with accusations of plagiarism and piracy, with a lot of people shrieking about how they took the blue bed in the game and made a red version, then some THIEF came along and did a red with yellow polka dots version.
And I'm not even going to get into the flame wars about inappropriate content, except to say that you could find a parallel Sims version of every single controversy in the RPG community.
I'm bringing all this up as examples of a downside to commercialism or a proprietary attitude towards creative content made for a hobby or game community. Ideally, what you want is people sharing their stuff with the rest of the community for fun, with the most talented people occasionally charging for a product to pay for materials, or so they can buy other people's stuff or go to conventions. The emphasis would be on being creative, with money as a secondary issue. But the reality is that a lot of produce content to bolster their own feelings of self-worth, and they see a commercial product as the means to do so. I'm not so much concerned about the commercialism, here, as the narcissism. We all want a little attention now and then, but if you're putting a dollar value on the attention you receive, or some other non-monetary but equally meaningless value, and obsessing about hitting some numeric goal instead of producing something interesting, you're going to be disappointed. And you're going to produce sub-standard content.
This is where I think some of the critics of commercial RPG hobby press products might actually have a point; it's just that they're obsessed with the money aspect, which is irrelevant, since forbidding people from selling their RPG products (and punishing miscreants with piracy) will not make the products better. Not all of the shrill people in the Sims community were actually selling anything; they were concerned about their crap not getting as many downloads as some other crap ripped off from their rip-off. Even in the case of not-so-narcissistic creators, when they start having to deal with order fulfillment issues, operating a business, and meeting legal requirements, that all eats into time and energy they could better use actually creating the product.
When you create because you want to create, that's great. When you create because you need a product to release on some schedule, to meet some goals that have nothing to do with creativity, that's not so great. It leads to taking shortcuts, or regurgitating material we've seen before (it tasted great going down the first time, but not the second or third time...)