Lol, the question was pretty much rhetorical and contextual. Maybe your attempting an Argument from Fallacy approach? As I am not really seeing your actual point.

The context of the question was:

"Actually going it alone is probably one of the options with the highest risk, cost overheads and workloads. I think if you did a cost breakdown per unit you would find that what most marketplaces take as a cut per sale is entirely reasonable considering what they offer in return. In fact I do not think I could name a single vendor in this market sector that sells exclusively through their own site? So I'm not sure where the proof of concept is here?"

The first sentence of the paragraph entirely relates to "going it alone" as a vendor and not partnering with a major marketplace, which was the thread context leading to the comment. The question relates to the fact that there are such a small amount of vendors that do choose to go it entirely on there own, without any partnership with the major markets, which indicates that it is the lesser chosen of the paths possible though to market for content, generally this would indicate it is also the more difficult path. The answer you provided proves only that their is a very small amount of vendors going it alone, which verifies the initial context.

And why does it matter whether the majority sell through large brokerages or not anyway? That has no relevance to the issue of a vendor's potential for success with selling through their own site. It wouldn't matter if you were the only vendor on the planet who sold through their own site, as long as you're getting enough traffic to that site and sales to make it worth the endeavour.

Are you truly serious with this statement? "No relevance" it is completely and entirely relevant. Market is one of the most major factors in any product or sellers chance of success. Don't you think if it was easier and more profitable to sell through an independent website, the majority would participate? Seems like your saying because we don't see many people attempting to flap their arms and gain the power of flight, it doesn't mean that it isn't possible to do so if you flap hard enough... Of course if you have more traffic then all the marketplaces combined you will be as or more successful then they are, the hard part is actually getting that traffic. Just to put it into perspective Xurge3d.com is ranked about the 1,900,962 mark for global site traffic ranking, Daz 3D is 10,206. I wonder how many more customers that translates to in the long term? How much more brand exposure? How much more increased chance of being successful as a content producer in the long term.

Some vendors even use brokerages as lead-ins to their own site. Kind of like free advertising - that pays you.

Or kind of like a dependence on a larger market for upstream click through to their own site? That kind of setup could also be described as a parasite market I guess. Which is fine if that kind of approach appeals to you. Though the practice may be at the expense of the host in the long term, especially if it is more widely adopted by others, and in time it may flow on to be your expense.