This all presupposes a super car has to be polluting but this is not the case.
Agreed, there is a few % extra in engine output by running slightly rich at the expense of much reduced economy which in general equates to reduced efficiency.
Running rich will produce more soot (particulates), and increase unburned hydrocarbons, CO will increase, with a lessor increase in CO2.
Yet the small increase in power could be obtained by a slight increase in boost pressure, this may increase NOX but the target is set quite high for petrol powered vehicles.
Of the reasons I can see for buying a super car, apart from, 'mine is bigger than yours', and 'hairs on your chest stuff', would be, 'look at me I can afford the very best', meaning the very best in all respects.
Sports cars were not really about speed, in their day, they were designed to go around corners better than the, 'normal' road car.
To achieve this, they were lighter, (leaving the roof off was one way of doing this), and had better suspension optimised to for cornering speed.
Higher cornering speed (in the UK) gave shorter journey times.
Inevitably, the run of the mill cars, improved, and it was found leaving the roof off, made the chassis flex, needing more design effort to correct, and more weight.
The weight could be compensated for by bigger engines (more weight), so now brakes became a big problem with all the extra weight to stop/slow.
But the target was still, a vehicle that would go round corners quickly and safely, related to that time.
Further development (much derived from racing cars) brought in, independent suspension, various chassis configurations, then monocoque construction, rack and pinion steering, all quickly adopted for normal road cars, leaving sports cars with very little advantage.
Sports cars could still have suspensions optimised for cornering, in contrast with road cars a compromise between road holding, and comfort but even there production saloons are closing in on the sports car.