damages

There's another potential option.

Simply use a bootleg z/OS.

In court etc, IBM is required to show damages. That
is the point at which you can effectively buy z/OS.

The court will probably even demand that you get a
proper licence, at which point you can say "um, does
that mean IBM is required to sell it to me?". Then
you've effectively got a court order in your favour.

There's a reasonable chance that IBM will be hauled
over the coals for predatory practices in the whole
process anyway.

Again, usual disclaimer about not being a lawyer.

BFN.  Paul.