Eh. The principal-agent problem can't be disposed of so easily as that.
There's no amount of compensation and excellent work environment which can provide enough upside to make founding a whole company pointless. Better expected value because of lower risk? Absolutely. But not total potential upside.
I say that as someone working his dream job, who can't imagine trading out for mere money. But I can imagine leaving to found something, though I have no intention to do so.
And the converse: if someone has that a strong desire to found something that happens to be similar to what they're currently working on, do you really want them to stick around only for a contract clause, when their heart's no longer in that work?
Wouldn't it be far superior to be able to have an open conversation with them about it?
(I also object to the premise: a desire to found something doesn't show up in a vacuum. There's something else that founding something brings (independence, permission to try ideas, small chance at wild stacks of money, whatever) and many of these should be negotiable also at your current employer.
Any good long-term organisation has a few crazy projects that just might turn out to be the next best thing. Let this person "found" one of those, in house and with freedom but full support of the rest of the organisation?)
There's no amount of compensation and excellent work environment which can provide enough upside to make founding a whole company pointless. Better expected value because of lower risk? Absolutely. But not total potential upside.
I say that as someone working his dream job, who can't imagine trading out for mere money. But I can imagine leaving to found something, though I have no intention to do so.