The markets for bespoke shoes and bespoke suits are so different that I don't think you can draw any meaningful lessons from the G&G example
Well, the new site is up, and it's tempting. The range seems a bit limited - 20 shades of navy and charcoal - and you're left to figure out from a single photo of each the differences among the various styles. Price is outstanding. I notice that depending on how many suits you sign up for, you get differing levels of service, ranging from entering your measurements online to getting a measurement from "a member of the English Cut team" to having them taken from Mahon himself. No second fittings of course. There are some interesting corner cuts, like only having two of four cuff buttons operable. I wonder how extensive their in-person measuring is, relative to typical MTM.
All in all, I think if I were in one of the cities where I could get measured by his staff, I'd sign up - just to see if nothing else. But for me, traveling to NY, hotel, etc. could triple the price of a single suit.