To my eye that belt looks like one that has been run at the limit of it's ability to handle heat and stress. Do you tend to run your 7060 at high RPM & the AC turned up?
There's a lot that goes into the V-belt versus flat belt versus tooth belt debate. The other day I was reading a technical paper about belt and pulley design. This one wasn't about wear or lifespan so much as being about the sound that a belt makes as it constantly traps, compresses, and then releases air. I'm always surprised at how little I know....
It turns out that flat belts and toothed belts have a bit more of a problem with making noise from air compression than V belts do. V belts can leave a space at the bottom of the "V" on the pulley for an air passage. Apparently that helps..... I had never thought much about it.
As with a lot of things that wear, the real solution to wear and noise on belts is simple and the same as wear & noise generally - just design whatever you are drawing up to be a bit larger and run it slower. There's a theoretical efficiency advantage in smaller&faster that doesn't translate well to the real world where things are often more efficient larger&slower. The downside is that designing components - like say an AC compressor - to be a tad larger and run a tad slower tends to cost more on the manufacturing side.
enjoy,
rScotty