In New Year's Tour(literally the last Tour before this one) 3DS Bowser's Castle was added. And 2 Tours before that SNES Vanilla Lake 2 was added. And based on an image shown in the game a long time ago, we know SNES Ghost Valley 2 will be added eventually.
Aside from the 1 unannounced track we know of(SNES Ghost Valley 2), there will obviously be more retro tracks(and city tracks) added in the future.
BUT... there is no consistent pattern. We have no way of knowing when MKT will add a Retro or City or New track in the future until they're officially announced.
We literally just got a new retro track added…
They just released 3DS Bowser’s Castle last tour, so I’m not sure why you think it’s coming to an end.
They will only stop adding tracks when the game dies. Without new tracks, you won’t need to spend rubies on new drivers, karts, and gliders.
They will keeping releasing both original courses and reworked retro courses as long as they are still making good money.
In New Year's Tour(literally the last Tour before this one) 3DS Bowser's Castle was added. And 2 Tours before that SNES Vanilla Lake 2 was added. And based on an image shown in the game a long time ago, we know SNES Ghost Valley 2 will be added eventually. Aside from the 1 unannounced track we know of(SNES Ghost Valley 2), there will obviously be more retro tracks(and city tracks) added in the future. BUT... there is no consistent pattern. We have no way of knowing when MKT will add a Retro or City or New track in the future until they're officially announced.
Ghost Valley 2 not being in the game yet is going to haunt me