Chance of making much, much more money
Control your own destiny
Lots of uncertainty
Chance of losing money
Lots of hard work
Ride in somebody else's boat
By the way, have you actually tried to sell rights to that patent? Make an informed decision. Something like a patent is worth what a buyer will pay for it. Most patents, the vast majority of patents, have no buyers.
And then there's the problem of the buyer who offers a royalty for a license, then does nothing with the patent. You make no money.
And, on the other hand, there's also the chance that you try to build a business and fail. Lose your shirt. Lose your house. Which do you prefer--a bird in the hand, or a successful business that you build yourself in the bush?