Really? I know that's the rationale, but I haven't noticed any appreciable difference between softs and hards in terms of tyre wear.
Usually because we're not looking. It's the fuel load that's been the determining factor in every event.
That's due to a few things; firstly, we don't care about either the fuel used or the number of black marks we leave on the track. In reality, there are limits on the number of tyres used, and a lot of the time it isn't a lot. That causes a knock-on effect; you don't use the tyres hard, you don't need all the available power. You want to last the entire race without issue, you don't use all the power. You don't want to pour money and wins down the drain.
You don't use maximum power or maximum revs all the time.
In the game, we have:
1: unlimited rubber
2: unlimited fuel
3: unlimited engine life
4: Trevor, the magical grease-digesting projectile-vomiting GT Auto oil changer.
I basically comes down to PD hauling the brakes on with realism. That said, if the game did wear through engines which you had to pay to replace, chassis you had to pay to replace (or buy new throughout a season), clutch components and gearboxes that you'd have to re-buy after say 2000km. Fuel you had to pay for, and a new set of slicks that cost credits. That's hundreds of thousands of credits per race potentially.
As long as that level of realism isn't there, we won't care about any of those in-game. And that's why in A-spec and B-spec we can pull of strategies that wouldn't be possible.
Also, PD needs to sort out their tyres, it's almost as bad as the abomination that Bernie is forcing on F1. Really, this is the closest I've been able to figure them out to be:
Comfort:
Hard: Mine Fuhrer brand rubber. Good for the Beetle, VW Bus and the wagens. Probably has a swastika somewhere on it.
Medium: These are what's on your mother's car
Soft: Sporty tyres, good for things like the Alfa Brera and such
Sport:
Hard: Daily driven track tyres. Think Elise, Corvette Z06
Medium: Cut slicks; something that would be on a M3 CSL or an Exige.
Soft: You put them on your track car, drive to the track, race, drive home, buy more tyres. Dedicated rubber for track work.
Racing:
Hard: Hard tyre
Medium: 'Option' tyre
Soft: Experimental Pirelli Group C qualifying tyre, that somehow lasts 17 times longer than it should.
On the off-chance you're driving a car that doesn't chug the juice like nothing else, you can notice a sizeable gap between the life of a Racing Hard and a Racing Soft. The gap only exists if you're driving both the right way though. Go easy on the hard and it'll last laps longer than you'd think. Drive the soft to the limit and you'll be pitting a lot more than you currently are. Drive the Soft's not to their limit (but faster than the hards that are being overdriven) and there's nothing in it.