Some moves/problems seem to take a particularly high toll on shoes. For example, I tore a chunk from the sole of my solutions using the high right pebble on deliverance necessitating a £35 resole. But given that i did the problem that was a cost i was happy to incur! Given i spent £50 on petrol just getting there the cost of shoes is small fraction of my outlay!
At the end of the day one of the nicest things about climbing on grit, the friction, is inherently bad for shoes but as fatdoc said i think you'd struggle to find a better value outdoor sport (even with shoe prices rocketing!)