There has been an attitude for a long time that "sim = difficult to drive" and "arcade = easier to drive, fun", but I've never agreed with it. Everyday people are able to drive real cars with no problems. I even saw a TV program where they put everyday people into an F1 car, and they were quickly able to judge the limit of grip on corners and corner at speeds similar to pro F1 drivers. There's no reason why FH6 should have any worse physics than FM, there's nothing difficult to drive about the cars in FM, indeed I find them easier to drive precisely because they drive more realistically.
The thing is, if we have:
FH series = open world, car collecting, carpg, weekly chores to unlock cars
FM series = race tracks, car collecting, carpg, weekly chores to unlock cars
then I see a 3rd game as being necessary:
3rd series = race tracks, true e-sports title with fair competition and equal access to equipment.
Otherwise I can't see there ever being a Forza game to compete with iRacing and ACC.
No, no, there was no Horizon series then. It's only pointless when you have another game that already has it in. If people want that same stuff in a game with real world tracks, just add those tracks into Horizon.
I'd also argue that the car collecting elements weren't what made the success of GT. When GT was released, it was simply the best driving game ever, regardless of the car collecting elements. I would have bought it on the day of release just the same if it gave you all cars at the start. In terms of real life friends at the time who also had the game, I didn't know a single person who thought the car collecting elements were anything other than a negative, an element that reduced their ability to enjoy the game. They played the game in spite of those elements, not because of those elements.