I've owned and played all previous 6 iterations of Gran Turismo, and I'm sorry to say I will not be purchasing the newly released Gran Turismo Sport anytime soon. After reading the reviews, I can't justify spending the proper $60 for a game with so little content and such draconian requirements in order to play.
The core attraction of Gran Turismo for me is the sheer number of cars spanning all eras and the numerous tracks I can drive those cars on. I can still remember the seminal moment it was to drive the full Nurburgring Nordschleife in GT4. The car and track count in GT:S is, without mincing words, utterly atrocious. Discounting all the variations, there's only about 90 unique cars in the game, a system shock to those us used to 600+ car libraries. GT:S only has six real-world tracks, which is bizarrely embarrassing especially when the main focus of the game is e-sport online racing utilizing the FIA license.
How did Polyphony manage to partner with the FIA yet only produce six real-world locations? Where's Silverstone? Where's La Sarthe? Spa?
The online racing component also brings with it an enormous negative externality: GT:S requires a constant Internet connection in order to play most parts of the game. I did not think ill of this until I found out that even non-racing portions of the game such as the amazingly beautiful photo-mode is locked behind the online authentication wall. If Polyphony ever decides to turn off its game servers (as it has for GT5), GT:S as constituted today would be no more than a drink coaster.
GT:S would need to the following updates before I part with my money: massively increase the amount of cars and tracks, add more single-player campaign events/races, bring back dynamic time/weather (how they have regressed on this from GT6 is baffling), and get rid of the online connection requirement for parts of the game that obviously don't need it.