I buy a set of tires every year(I do A LOT of driving). You don't replace your suspension parts that frequently. Money is less of an issue on something that becomes somewhat permanent.
Besides, what does it matter if you most people have a different set of rims for the track?
Personally, my car is pretty much stock and I'm not trying to get any tickets or into an accident. If I had time/money to go to track event, I'd have another set of rims/tires for that. I also have the stock '95 calipers(for now). If I'm not pushing the limits of my car, why do I need a super expensive tire?
IMHO, most 245-45-17 tires are gonna grip better than what other run in their daily drivers, so we're already better off.