You don't have to have an exit if you're a bit more creative with how you extract money out of a corporation you've set up for that purpose. The most ethical is through getting a solid salary paid out to you. Least is outright embezzlement - find a front who doesn't actually have your real name, convince them that the VCs can't know that this is actually your idea so they have to hide your involvement, and disappear with the cash leaving them holding the bag.