With all due respects that is a matter of opinion, and you are entitled to yours. From the opinion of a PhD in Engineering there isn't anything that is new on the Summit X that couldn't be incorporated into a few new PCBs for the older Summit. The ESL panel is the same, the woofers themselves are the same, the woofer amps are probably the same, the cabinetry has the same dimensions ( they did not even incorporate the Ecoboard from the CLX???!!!!...shame shame). The new feet are neat, but as we have already seen on this forum a good machine shop can easily create longer feet for the existing Summits. The downlighting is a farce, designed to appeal to the "tuner" crowd that does the same to their cars to give them some of the faux pizzaz that they lack in performance. I think most of us here could live without it.
All the real changes happen in the electronics...which have already been designed (for the Summit X). The just may need to be repackaged onto PCBs that will physically fit the older Summits. I know you're not a design engineer so I'll tell you that it's much less of a task than producing one issue of ToneAudio magazine. When I was configuration manager for the F/A 18 (which is nothing more than a flying computer) we could turn around new PCB designs into boards in 5 days...and that was nearly 20 years ago, things have gotten much easier since.
I for one as a Summit owner wouldn't spend the coin for such an upgrade. As an owner of their former "Flagship" I just get infuriated by the crock of dew dew that they are telling us that it's not possible, and expecting people like yourself to give credibility to their statement that it doesn't have on it's own. Don't you/they realize what you do to yourself by perpetrating the myth?
Instead of perpetuating the myth it would be much better if ML just came out and told the truth. It's not the technical issues holding up an upgrade; it's the $$. The accountants have veto'd any development $$ for them to produce such an upgrade. That sort of statement we could respect.