When GT Sport was launched, it was largely advertised as an online game, and therefore it made sense to request players to be online. With the numbered Gran Turismo 7, things are a bit different as it goes back to being a numbered title and offers a fresh take on the singleplayer campaign.
But even if singleplayer is what you favour when it comes to racing, you will still need an online connection at all times. This was revealed in the fine print on the PlayStation Blog where it clearly says you also need an internet connection for the GT Campaign mode, the Livery Editor, Scapes (the photo mode), GT Café, GT Auto and more. It basically seems like you will need internet for everything.
This should not be an issue for most gamers, but as least now we know.
Thanks, Push Square.