IBM could sell the future of the on premises z/xxx boxes as "datacenter in one rack"
Running x86 in z/VM has been a discussion for 25 years. Just fucking do it. Let people run whatever they want.
Just as people are excited about ARM for low-watt computing, make s390x just as exciting for people who want insane vertical resources but using the same dev tools that are used now for easy x86/ARM crossover.
But IBM culture has always been about overcharging a small and rich audience and now they are sitting around hocking their services cohosted thru AWS and everyone who has COBOL and 360ASM running are doing retirements with no plans to use the boxes after its all unloaded.