@KC2684 I, too, am facing the same hurdle you have with your MBP. I have a 2015 Retina MBP - same story - XP12 simulator isn't useable but I will use XP12 PlaneMaker and AirfoilMaker for development tools on the MBP.
Totally my own perspective; the sense I have is that the way forward in the development of the sim software by Laminar is to leverage the GPU and VRAM more, taking the burden off the CPU and mobo RAM. This will allow for a better looking sim environment.
Since the release of XP12 I've begun planning my next computer build - I haven't built a new Windowz box since 2011/12, I upgraded the video card to a GTX1070 in 2016, maxed out the mobo ram to 32GB at some point as well, it runs XP12 decently for me but I know its future is limited.
I was surprised when I started looking at the new Intel CPUs; core clock speeds aren't really any faster than the i7 2600K I currently have. The big difference I see now is the number of cores now on the CPU die.
For X-Plane to advance in features and maintain a customer base, there needs to be advancement in more than just flight model dynamics and performance. I've very happy that FINALLY Laminar Research is embracing modern video codecs and leveraging the power of the modern GPU; OpenGL has its place but it certainly isn't the way of the future, or even the present mainstream.
Here's to the future of X-Plane (cheers) I'll have to save some doubloons to build a worthy computer box...This is The Way...