I was in this situation once. I joined, recruited the team, built the product... only to discover he couldn't sell it. Sales were abysmal. He could raise money and "sell the dream" though. That only goes on for so long without results. He also refused to pivot after 5 years of slow growth.

Company nearly went broke and was "acquired" by one of the investors for pennies on the dollar. I say never again... but, I like early stage companies. Maybe not that early.