While I understand your concern, I'm not sure I agree. Investors have an incentive to make their investment profitable. Therefore, if they have to maintain a level of effort for an investment, they'll do everything to make it grow. That means they'll work to widen the community without making it too broad for advertising, work on building in organic advertising, etc.. Having given it thought for six hours, I really do believe that keeping mods and investors in alignment will be important. It's the reason why the fediverse tends to work; those who have the financial investment are the moderation team.