It is in some way tied to the site (renderosity, runtimedna, etc) and in some way to the software (Poser & DazStudio). For some reason i do not know (perhaps because the Poser 4 woman was too well suited for pin up renders?), Poser and its main content sites specialized in the Naked-Vicky-in-a-Temple genre. Other sites/software specialize in different things, too. For example Vue is used mainly for rendering landscapes. There are characters for Vue as well, but the main content market focuses on various kinds of dirt, stones and plants, and the reason for that is not that there are more plants and rocks on the planet than there are humans, they just specialize because they want to (or need to) excel at one thing instead of being a jack of all trades.

If it were a universal rule that mankind wanted to see naked Vickies more than anything else, it should be common to every software and content market, but it is not; at turbosquid for example there are more male figures than female figures, and no particular lamenting of the vendors that the male figures do not sell well (at least not as far as i know). There is even one site (maleposerrotica.com), which has specialized in the male figures for poser, and if the demand for male figures is big enough that it can support a whole website (admittedly a small website), it cannot be that small, i think. It is just small here. So if you take a software specialized in naked-vicky-renders and visit a website specialized in naked-vicky-renders, i am not particularly surprised that male poser figures might appear to be somewhat underrepresented at renderosity (or runtimedna, or daz for that matter).