Where's the ROI on InTune? (A.K.A. Let's talk licensing)

So at Ignite there was a ton of presentations on the boatloads of time and money we were going to save by moving to InTune.  We renewed our EA just a few months ago and InTune/EMS was a straight up $7 million dollar increase per year for the whole org.  The savings from moving away from SCCM: $0.  I can buy an incredible amount of infrastructure and hire Johan and Mikael for that kind of cash.  So InTune is kind of a hard sell at the moment. 

I'm in retail and the overwhelming majority of our boxes are kiosk-like devices.  We don't even bother with domain joining them at all since they are so single-use and user agnostic.  When we looked at InTune it is so user-focused that it simply couldn't do the things that AirWatch does (not my project so I can't really give specific details personally ... I just know that was the outcome).

So the answer I'm well aware is to run InTune where it makes sense and SCCM where it makes sense.  I don't see how we save money by having multiple systems for different parts of the business.  SCCM works beautifully at scale and simply subtracting 5k from a 25K install base saves ... nothing .... absolutely nothing in terms of infrastructure or time.  That makes InTune simply a pure additional cost without any savings that I can even theorize much less prove.