Interesting point bringing up Van Gogh, an artist who struggled financially and killed himself. His art certainly isn't worthless today, but it wasn't until years after his death that it really had any value. Admittedly, it's hard to say whether or not fame and fortune would have helped him, he might have felt more appreciated and been able to afford better healthcare, but it was also at a point in time where we were still limited, especially when it came to mental health. Really though, this debate is just silly. If Game developers don't get paid, then they aren't going to be able to make games. Same with musicians, directors, writers, and all the other people involved in the business. Yeah, when you buy a cd/game/whatever it goes to the label/publisher/producer and not directly to the game itself. There's a middleman, but there needs to be one. You can't make an awesome game/album/movie/show/whatever else without first having funding. The product in question might go on to make millions of dollars, but without having that initial funding they either A. Aren't going to be able to get off the ground in the first place, B. Won't be able to offer their product in their desired format, having to essentially go "low budget" and as a result charge considerably less because of all the features they're lacking, or in certain cases, C. Use a bunch of existing profits to fund their own product and ultimately fail to make the money back due to pirating.
So yeah, you're not paying the makers themselves, but you're paying the people who fund the makers and are ultimately responsible for them being able to get their product out there. There are some exceptions, especially with the music industry due to the internet, and there are certainly lots of indie games and products that can be considered successful, and some of those self published games/shows/whatever are certainly awesome, but if you talk to those people one of the things that tends to get brought up about how they would love to do awesome thing X/Y/Z, but they couldn't because of lack of funds. This happens when you have a huge budget too, for example, listen to the directors commentary for The Avengers and you'll hear about all the awesome things that they wished they could do if they had a bigger budget.
In a perfect world, yeah, we wouldn't have currency and people could have unlimited funds and just make these awesome amazing projects that everyone could enjoy, but that's simply not how the world works. Being successful doesn't mean that you lose your artists integrity. That's such a vague term anyway, I mean, art can really be described as anything that you're especially good/creative at. You wouldn't ask a chef to cook for free simply because it's their art, or a doctor, or a detective, or *insert your own job that you're good at here*
And considering that people still pirate products even when they do come from self publishers and the like, the argument still holds little merit, it's just people trying to justify to everyone else that they're not stealing with their pirating, and that it's everyone else who's wrong for not letting them have something that they want for free.