The problem with that is that you can never know that the hacker didn't
also sell it to someone else.
This is also one reason AMD would never pay a ransom for it - because they can't be guaranteed that all copies were destroyed, and therefore it could still end up in the hands of their competitors.
If it's the IP for an entire cutting-edge GPU, it's actually pretty cheap. For one thing, look at the revenues AMD generates with these products - it's in the $Billions, annually. As another point of reference, a Chinese company is believed to have contracted AMD to build a custom APU for the Subor Z console for about $60M:
https://www.anandtech.com/show/13381/subor-z-console-pc-hybrid-fireflight
Of course, that includes CPU cores and the firmware, drivers, and probably other services needed to get the whole thing running and pushing pixels. But, if you have the IP, you could theoretically make multiple generations your own chips.