BlackBerries are widely used by people with limited free time whose primary focus is making business.
Being so many years in Software Engineering, have you met a real demand for games in BlackBerry? Do you think that persons with this specific profile would use their BlackBerry for entertainment? In other words, would they invest some time playing games?
Sure, why not? Just because you select a phone that's optimized for business doesn't mean you're all business. Everyone knows executives like toys (maybe a golf game? )
Also note, many people have a BlackBerry because their work requires them to (or gives them one). A company can place security restrictions on company devices to prevent people from loading third-party apps on the device, but they don't always do it.
I'd like to add that , there are a lot of new blackberry consumers , that don't really belong to the business segment . They would be interested in any good games .In addition , a lot of business segment users don't have access to third party apps from their phone . So the lack of demand from "business" users should be the least of your concerns .
My two cents.