Earlier quoted context omitted.
No, there's a hard upper limit on ransoms; the cost of recovery.
What about when the cost of having the data exposed to the public is higher than that of recovery
Arguably the bigger problem is you don't know that the ransomer will actually give you a valid key, but suppose you guess a likelihood P that they do.
Now you have some scenarios:
1. Don't pay. We're out $C.
2. Do pay, and get a valid key. We're out $R.
3. Do pay, and get no key. We're out $R + $C.
So the limit is at scenario 1 being equal to the combination of 2 and 3.
Set C = PR + (1-P)(R + C), and your max ransom R = CP
(You could probably work in additional costs for cleaning up even if the ransom is paid.)