37.73 miles is longer than Imola, Mugello, Aragon, Hockenheim, Vallelunga, Estoril, Hungaroring, Okayama, Autopolis, Sugo, Zandvoort, Zolder, Knockhill and Oulton Park put together. Or longer than Road Atlanta, Watkins Glen, Road America, Lime Rock, Sonoma, Mosport, Mont-Tremblant, Circuit Gilles Villeneuve, Interlagos, Portrero de los Funes, Ordos, Algarve, Mores and Magny-Cours put together. I know it's not an apples to apples comparison in terms of cost, as on the Isle of Mann you only need one license and there's no need to transport all the equipment from place to place, but I think it gives a hint to the scale of the scanning and modeling work that needs to be done to include such a course.
I think this course would be a luxury that Gran Turismo isn't ready for yet, as the real world track selection remains patchy and limited. The rate that PD is adding real world tracks to their games has been slow in the past and a monumental project of this size isn't likely to improve that. I'd rather even just 4-5 usable permanent racing facilities to this behemoth.
If it is included, it would once again indicate that GT is more keen to sell out to marketing than it's rivals. Nobody else is wasting their time and resources modeling 37 mile tracks rather than focusing on usable tracks.