Quite simply - tuning doesn't matter to casuals. They just won't do it or even know you can do it. So they don't care, and numbers don't change.
But on the other hand, you can't ignore a long race, it's fundamentally just part of the race - and so if a casual doesn't like the length, they won't do it at all.
Sport Mode ultimately boils down to one major problem, and that is that it has to appeal to the lowest common denominator of player to pull in respectable numbers, but what casual players are attracted to, isn't what many regular or dedicated sport mode players constantly want to do.
The issue here is that most of those regular players WILL drive slop combos. They'll complain that it's slop, they'll be annoyed that the combos are slop again, but they'll still play.
If a casual sport player sees a combo they don't like, they don't play, and the numbers go down. That's bad for the game, so the combos stay sloppy because both parties still play.
A casual player won't play a unique combo, but a dedicated player will still play a boring repeat. PD likely prioritise what gets numbers, and because the dedicated players play slop, we get slop.
