SA is relevant to larger organisations who have take DR seriously and need to failover hundreds or thousands of Windows VMs to failover sites. Instead of licensing for the primary physical virtualisation hosts, and the failover hosts, you only pay the SA percentage on top to license both and can failover at your leisure.
To the small fry with 5 Windows servers and a couple of old Linux boxes who think they're Mr Robot, the real benefit of these 'outrageous' and 'extortionate' licensing schemes is not something easily grasped.
That's not to say I disagree with the terms 'outrageous' and 'extortionate' with respect to some MS licensing (ahem SQL server Ent ahem) - just that their offensiveness is dynamic based on the scale at which you're looking at these costs.
ROI calcs, based on hard facts not Utopian whims, can often have surprising results....
I also believe that you can run a medium-sized enterprise's IT environment, from desktop through apps to servers and virtualisation, a lot cheaper using MS Windows over, say 5 years, than attempting to run a purely non-MS shop of the same scale, with the same requirements, same results, same end-users IT literacy (lack thereof) - mainly because I believe this sort of environment can be built and run by a smaller, cheaper IT technical team than an equivalent *nix environment.
Reminds me of the classic adage: "Linux is only free if your time has no value". Of course things have moved on a lot since that phrase was coined but in terms of enterprise requirements (not a farm of web servers, or containers, or Facebook\Google, or specialist requirements - real-world enterprise log-on-and-do-your-work environment), you buy MS Windows and hit the ground running. Fast.
MS know what these companies want and expect from their IT and IT staff, and what they're prepared to pay for it. And yes stretch it a bit. OK a lot.
Of course this is just now, and will change over time. And that is a great thing about our industry right?
Biting the hand that feeds IT
