is there a cutoff period after which you would rather die than be revived?

Somewhere between a few years and a few decades, I think.

(IANAL) I think that would be a very simple clause to include in any freezing arrangement.

The extremely small chance that cryonics will work within that time doesn't justify the expense.

But for those who can afford more, it would be interesting to see short-term cryonics added to a health insurance plan.