Why did you assume that a rally is always disputed on dirt/snow roads?
There are several blue ribbon rallies that are raced on tarmac roads exclusively, like Tour de Course (F), Rallye Sanremo (I), Ypres Rally (B), Rally Japan (J). So it was usual in the past cars racing in Tour de Course or Sanremo and nowhere else because it simply wouldn't be competitive anywhere else. One very good example was the BMW M1, a track minded car that raced Le Mans but also participated on Tour de Course. But no one ever saw a M1 on dirt tires or on a dirt/snow surfaced rally.
Some countries even have separated championships for tarmac and dirt rallies, like France.
The Alpine A220 indeed raced on rallies, as you can see on this photo, from a tarmac surfaced rally, the
Critérium des Cévennes:
Second thing, Gran Turismo doesn't have "rally races". They have circuit racing on dirt surface tracks.
Rally are raced against the clock, one car each time, winning which one sets the fastest time, not a field of cars winning which one crosses the finish line first. The stuff we have in GT7 is something similar to Autocross (closed circuit dirt surface, the more popular Ralicross is raced on tracks with both dirt and tarmac sections).
So, no one can go rallying in Gran Turismo 7. Well except Musical Rally where you effectively race against the clock and I think is the only race where the "rally" word is used, otherwise only references to rally cars, pointing to Group B cars.
