I am surprised that there isn't more offerings from Porsche (road-going 718/boxter/cayman, 918, and then maybe a 356, Carrera GT, and/or early generation 911 in one of the post-launch car packs), but your list is insanely large. The list you've just made is like two or three times as long as the list of offerings currently available from Toyota, which I'm pretty sure is the most-represented brand at this point. Plus there's a lot of near-duplicates, which thus far PD has been largely avoiding, especially post launch (aside from the dual M6 GT3s and Gr. X vs. Gr. 1 VGT variants, the closest duplicates would probably be the R35 standard and Nismo counterparts, FT1/Supra, and SF-R/GR concept version). You list at least four versions of the road-going 718, and several very subtle versions of various race cars, most if not all of which would be completely unnecessary or even useless in the context of GT Sport. We don't even have a function/grouping for the older race cars added yet, and your list would probably add an extra two versions of the 919 to Gr. 1 - it would just be bloating the car list, and making a lot of redundant work that could be used to develop a far more diverse car list. I don't think we've seen any other brands as well represented (in terms of diversity and racing history) even in any of the past GT games - giant lists/car counts, yes, but comprehensive and rich collections like you've just listed? Never.
It's not that I don't want more Porsches, but your expectations seem incredibly out of touch with reality.