Leading AMD must be emotionally exhausting. Can you image leading a company that for so long is fighting for survival?

This is basically every startup. Many of the quiet successes take decades.

This is most businesses in general where healthy and creatively destructive competition takes place.

Given the entangled licensing situation, what would happen to Intel if AMD went bankrupt? Would they not lose their x86_64 license, unless they bought what remained of AMD? And if they did, would that raise some major antitrust issues?

Depends on the license terms. e.g. if their license agreement says its irrevocable or "irrevocable unless <some action that blatantly violates the spirit of the contract>", then a future AMD buyer would not be able to retract the license just because they think they could get a better deal now. I'd imagine Intel's lawyers are good enough to get such a deal.

Is that reasonable though? I thought AMD was doing great with Ryzen and Epyc, and Vega is selling out as much as they can make.

AMD is BARELY free cash flow positive. They have been on the brink of running out of cash as long as memory serves me.

https://ycharts.com/companies/AMD/free_cash_flow