An exec worth millions/year in tech needs decent compensation to take the career risk of steering a declining company.

This is cartoonishly circular: exec needs millions/year because that's the only way to attract a person worth millions/year.

Why is that circular? If someone is worth that much then you must pay what they're worth to get them.

Whether they need someone that expensive is up to the organization to decide.

What are you paying for when you hire someone? "Someone existential wonderful presence", or "someone ability to do something"?

What about having a decent base salary, and a bonus of extra millions if your results align with the organization goals?

Saving a declining company will bring enough revenue for future compensation for the CEO. And who wouldn't hire a CEO that saved a sinking company? On the other hand, if the company still goes belly up, well apparently that CEO wasn't so good after all. So high compensation wasn't needed.