i'd say it depends on the type, quality and style of the shoes. I've got a pair of boots i paid $200 for in college. That was 10 years ago. They are still going strong. I'd gladly pay $20 a year for a pair of good shoes, so why not $200 for a pair that will last me 10-20 years?
I wish I could get that kind of mileage out of shoes I am just hard on shoes I guess, I had a pair of new balance that lasted me 8 years and I wore them almost everyday in the army for PT so when they finally got worn out I bought some more and they lasted 9 months, it also seems the more I pay the less time they last. Kind of like my high dollar badger brush in my shave kit only lasted a month and my 3 dollar brush works better and I assume is still good because I haven't shaved in 2 months.