Great question! If you truly want to maximize income/revenue, I would recommend sticking to businesses that are related and can take advantage of economies of scale. That will maximize Your profits and revenues. If your multiple businesses are unrelated -- Like in the old days a conglomerate, will dilute the power of what you and your team can achieve. Plus scaling unrelated businesses at the same time is the quickest way To wasting resources and not getting enough traction in any of them.