The article's revenue estimates are based on Rogan doing more work...setting up subscription programs, keeping up with YouTube's content policies to avoid getting kicked off the platform, and continuing to find podcast guests and creative material.
Perhaps he wants to kick back, not work so hard (depending on the contract he actually signed), and collect a steady paycheck? The author likens Rogan's podcast to sitting on an oilfield (where the value of oil can be easily evaluated), but creative endeavors are hardly so cut and dried.