It seems like, except for "Cracking the Mainframe" or whatever, there's no easy (or even moderately accessible) way of simulating a mainframe setup to learn. Again, I love this stuff. I read Redbooks in my spare time. I have Hercules and z/OS setup, and that took a long time to setup compared to an Arduino or firing up a Linux VM. An average HNer is probably like me -- he/she might want to fire up a z/OS instance and play around with it. But he has no way of doing it though.
These are the tinkerers who end up deciding what platforms to use down the road. The high school kids playing with those free STM32 micro-controllers that TI gave out was a brilliant move. When they choose to do their semester project junior year, they might stick with TI because that's what they know. AVR was lucky Arduino took off too for the same reason. 10 years from now, those high school kids are going to be choosing what to buy 10k units of to throw into the pick'n'place machine.
There are some interesting big-data cloud IaaS/SaaS offerings you've put out to keep up with the times but outside of alliances with large incumbent vendors (say, SAP in ERP; EPIC in Healthcare) to sell large modules, you're not going to see much traction.
Offer something the tinkerers can play with. Make that the gateway drug. Amazon did it perfectly with AWS - easy to roll out, pretty predictable pricing schemes, pay for what you need, and scale up (more VM's/larger VM's) or out (other products within AWS). Every other vendor is chasing their tail trying to capture that market.
Linux on the z community offers me nothing as a decision maker. If I was already vendor-locked into you guys, then the prospect is appealing. But even with low latency (operating within the u-seconds, m-seconds and people start losing jobs/panicing), five-nines SLA (healthcare, HFT prop trading) requirements, what does the Z platform have to offer? How can I even evaluate prospective costs when pricing this out to pitch to the (hypothetical) board?