Maximum profit is not the most important factor, but some level of financial health is necessary unless we're talking about one-and-done games.
For one thing, I prefer my game designers to be professional. I don't want them to be making games* as a hobby. I want them to do it as a full-time job – ideally as employees with a steady paycheck, but if not at least as full-time freelancers. Professionals generally make better stuff, because they get a lot of practice. And if they have real employment, that offers a sense of stability that lets them focus on their job instead of wondering if they can line up a new gig once this one is done. Professional game designers also means you'll be able to get a steady output of material, rather than having part-time game designers getting really busy with their day jobs or getting sick or stuff like that. I don't want to wait two years after the core book and the first adventure is released for the next adventure to be published.
And to have that sort of organization, you need to be able to pay those designers, as well as the overhead associated with having actual staff. And in order to do that, you need to sell stuff.
* I include the whole gamut of product here: core rules, supplemental rules, setting sourcebooks, adventures, whatever.