I think in many cases "more diversity" is just lack of available talent. For example CVR only books models who are in their location, they don't fly girls in from all over Europe or shoot in other countries, so I'm not sure their selection represents their ideal cast, it's more the best of who they can get locally that week. They also favor reliability, which is understandable, as flaky girls are money down the drain. So bottom line, their cast is due to a risk averse business model with a tight reign over the budget. I think Virtual Taboo hires more top tier talent, and I wonder if they have a higher casting budget? As for VR Bangers, they can't shoot for shit these days so casting is irrelevant. My condolences is the lifetime sub to such a spent force of a studio.
SLRO is a bit different because they have to try to appeal to a broad user base, seeing as they're a portal trying to be Netflix. If you don't like this week's models, there's always content from other studios to check out. Although I always want top tier casting, I can't complain too much if they make content that doesn't fit into the popular ideal of a perfect body / face / genre.
I'd say Wankz and POVR are fairly consistent in the type of models they book (or try to book). And Badoink too. Mostly slim hot young models with only the occasional variance.
But yes it's a much smaller market so studios will generally favor safe bets in terms of both bookings and genre.
