This is exactly it. When you're recruited (and you're always recruited - it's super rare to have a C-level position open on the website and submit a resume to) to a firm as an exec you have (generally) tremendous leeway to negotiate your own contract, exit criteria, etc.

Yes, the board provides a starting point, but it's much more collaborative negotiation - and you (as the incoming exec) are gonna negotiate based on the criteria I mentioned. It's not at all like an IC where you basically get a "take it or leave it, plus a few % more on salary if you push back" offer. It's a different universe.

Is it fair? I dunno. The "intrinsic value" argument doesn't really apply - the CEO is worth $10M/yr if the board thinks they are.