My advice, trust your gut. What matters is if it is a red-flag for you.
Good luck.
The danger is that they aren't in it for the long haul, are just using this as a resume padder, and are looking to jump ship to a VC firm (or potentially a better resume padder) asap.
I want to work at a place where the incentives are aligned in such a way that, if I really am some approximation of a rational economic agent, I would have no choice but to "be in it for the long haul", without having that be my intent on day one.
In other words: it is your job as a company to make a prospect stay there for the long haul; it is not their job to come in with that psychological state.
And yes, I'd like to work at a VC firm eventually.
First I want to find the right fit. Then I want to incentivise them. Is someone who wants a bit of "startup experience" before working for a VC firm the right fit?
'I don't think it's effective to "incentivise" someone to do a job that they fundamentally don't want to do.'
I don't even know what this means. I don't see how anyone "fundamentally" would want to do anything to help you with your company unless you incentivize them.