If I start a club tomorrow, and make it "open to all cultures as possible," that doesn't make it diverse. Diverse is about actual representation, not openness.
The Wikimedia Foundation has already targeted certain cultures/areas for development and are giving grants for development in those areas. So talking about whether particular groups should be targeted is moot: they already are.
My questions relate to how you get someone who is not a contributor to become one. Besides time-prioritization, there are also access factors: they've got to already be computer users. Then they've got to be internet users. Then wikipedia readers. Before those steps are taken, contribution is not possible.
Those who are already habitual internet users are more likely to time-prioritize Wikipedia contributions higer. I bet we could come up with a list of factors that make contribution more likely. Market research can do some pretty amazing things, like tell what occupations and hobbies make someone more likely to be a contributor. Even what sorts of products they own may predict contribution to Wikipedia.
To me the problem is simple (solution less so): We need more diversity and participation. This will require getting more contributors in groups that are underrepresented. That in turn requires getting people in said groups who are not currently contributing to contribute. These people already fill their day with other activities. We need to figure out how to get them to add Wikipedia to their lives. Adding 30 minutes to a 24 hour day formerly occupied by other things requires removing 30 minutes of another activity (whether that be spending less time doing something, or spending less time doing nothing doesn't matter...that 30 minutes has to come from somewhere).
The Wikimedia Foundation is targeting various groups through local chapters. I'm a member of Wikimedia Philippines. If the Wikimedia Foundation does research, and finds some ways to increase contribution, then gives that information to all the chapters, I highly doubt that Wikimedia Philippines efforts here will hamper the efforts of Wikimedia Norway.