I also think we'll see cars in the first months of 2021. We're six years into this iteration and they're saying they plan to keep it around for much longer. Somehow I don't think they'd do that without adding at least one or both of the most asked features - cars and babies.
Also, cars have been very present in both Evergreen Harbor and Mt. Komorebi. You could say they've been present since the beginning (in Oasis Springs for example), but they just seem to be everywhere lately. This is all just wishful thinking though.