I hope never!
Friend, GT7 first needs to focus on bringing the latest GT3 and GTE cars like BMW M8 GTE, AMG GT3 Evo, Ferrari 488 GTE Evo, Porsche GT3 R, Bentley GT3, as well as hypercars like Senna, Project One, Valhalla, Valkyrie , in addition to the IMSA DPis.
After that, you need to bring more than thirty real and fictional circuits, like Mugello, Algarve, Imola, Potrero de Los Funes, Watkins Glen, Everland, Red Rock Valley, Grand Valley, El Capitan, Apricot Hill, so then you can think about motorcycles.
I prefer motorcycles to be included in an eventual Tourist Trophy 2.
However, I have a feeling that PD-Yamauchi have no interest in TT2. That's because I think they want to create competitive Esports modes, and playing with the TT2 joystick doesn't sound "professional". Until they invent a motorcycle racing game equipment, I don't think PD will bring TT2.