It's possible IBM never dies, or even never shrinks, but stays the same as the world grows around it. That seems like the same thing.
There are plenty of too-big-to-fail companies that at the end of the day don't care if the project succeeds, just that if somethings goes wrong you have some definition of legal recourse. You buy IBM because you write in your contract "we agree to buy the necessary computers systems and software as require per our vender (IBM) and the vender will be responsible for ensuring compliance."
Sounds great to both parties, except the loophole doesn't say that the requirements need to be correct. If things go great, fine. If things go wrong, customer gets to argue with IBM. Good luck with that. IBM isn't known for their hardware and software in the computer world, they're known for their lawyers.