Well the downside to signing-if the startup isn't doing hot, or you realize a startup isn’t for you, your backup plan is a leadership position in your field of

Well the downside to signing-if the startup isn't doing hot, or you realize a startup isn’t for you, your backup plan is a leadership position in your field of expertise. Sounds very constraining. Also if you truly want to leave, it doesn’t seem like a great idea to keep you in a key position. Why force you to have this as an only option? You might even be incentivized to sabotage the startup! Seems your equity and the belief in the mission are really what would keep you there.