My experience tells me otherwise.
Please explain why the results from reading ICC swatches by an expert at a remote location using expert instruments would be inferior to those from the machine location.
I'm not an expert on color like you are but in my experience I have had two Mutoh ValueJets who's serial numbers were one apart and they were installed in the exact same room on the same day using the same inks. When they printed the first job using the same profile, there were slight differences and the quality was kind of grainy. After spending a weekend with a professional color profiler they made a few profiles and now they print consistently between printers. Now a lot of people are using 3rd party inks or Chinese vinyl that doesn't have any boxed profiles and the problems multiply.
Another example would be that we sold a printer to someone in Washington. We shipped it from here in Denver. When I installed the printer for them I used the exact same profile I used to demo the machine in Denver and it laid way too much ink down. I had to find a completely different one to work properly.
So while I trust and respect your experience, you are always teaching me new things about color on this forum, my experience as an installer has been different. Do you not profile on site? Do you have customers send you printed files that you profile at your shop?