I agree with that, TBS is just a completely different taste from FBS. In FBS, you'll enjoy driving extremely fast on the modern European highway, exploring some cities in mini shape. But TBS doesn't, it is about solving the puzzle, collecting items, managing company and finding some secret hidden on the island. IMO, driving is more challenging. You could not drive so fast as in FBS, on one hand, you will get flipped, on the other hand, you would miss the beautiful scenery and interesting locations along the route. It is really a tough test for your driving skill.
For The Bus, I can imagine something now. It might be about the busy traffic, sticking to the schedule, or even the Berlin Traveling Simulator.