My last several new sails from North and earlier from UK, could not have been "three times" more expensive than any other possible source.

I say that because no loft anywhere could have built a dacron sail for 1/3 of what I paid; more like half or 2/3; and that would be without any on-boat measurement and setup.
(Decades ago, for a few years, I was a local rep. for a national sailmaker and always sweated bullets over providing enough measurements and pix to eliminate errors -- or at least errors made by me.)
That particular multiplier (2X or 3X) just seems very difficult to believe, to me. I now work with the local loft and stay in touch with 'em, and maybe (no proof, tho) get treated better for both service and price than some other one-shot customers. Not really sure of that, since we only need a new sail every decade or so. (?)
Presently our North jib was just dropped off for minor chafe repairs and checking of stitching. Next will be our main for the same sort of attention. Since neither of these sails are white dacron, but rather a step up in material, there is likely no way to compare them to a sail from a bargain loft. When you factor in personal service and knowledge, comparisons are more difficult.