I know this correlation may be weird but i NFS 2015, splatoon, and overwatch having little to no single player activity.
Just like GT Sport, These games lacked a proper single player mode.
Splatoon had a single player mode, but its lackluster and has little replayability.
Overwatch and NFS 2015 did not had NO single player whatsoever. Matter of fact you cant play the games without internet access. NFS fixed this problem with their upcoming game Payback.
When im visiting a relatives house that have no internet. i take games that have offline singleplayer, like mario kart 8 dx or f1 2016. I hope GT Sport wont be a online only game like NFS 2015. Thats like buying a lock without a key that can unlock it.
I just hope PD realizes this fault and for future GT games, to includr a proper single player.