The Pirelli Superbike Pro's are garbage first off, they're a stiffer rubber so they last longer, but they don't work well. Second off, no tire is designed for 7 track days, what are you crazy? Shit, I burned through my OEM Diablo Corsa's on my 848 when it was new in ONE track event, tires were shot. Thats back when I didn't know how to ride! Tires simply can't handle the stresses and it absolutely amazes me you got around the track without crashing.
As a reference, Diablo Superbike Corse tires, the "real" slicks, last about 20 - 30 laps at a decent pace. The Superbike Pro doubled that length of time to 60 laps, but with substantially less grip. Mind you, those numbers are using warmers set to 170F in between sessions and proper tire pressures.
So if you do 6 laps per session and 6 sessions per day thats = 36 laps per event. That means, after two events, you're tires should be toast. The problem is, you may not even know what a good tire feels like because the Superbike Pro is such a piece of junk, it may not even give you the feedback necessary to go quick. Thats one of the reasons I switched from Pirelli to Dunlop and started immediately picking up speed, because the Dunlop had so much more feedback and grip.
All of that to say… yea, the numbers simply don't add up. That tire was shot after your 2nd track event and you just kept riding it because you didn't know better. Does it take wadding up the bike to finally put new tires on it? Remember, those things are the only thing keeping you up, so its something MOST people simply don't Eff around with. Warmers will help a lot, you may get 3 events out of a set of hard compound slicks, but with substantially reduced grip.