These are my Mizuno Enerzy. They are only a few years old, but they survived my 110kg to 75kg, 5km in 50 mins to 10km in 55 mins fitness journey. Its getting a bit embarrasing at the gym when people see the duct tape. Ive already stitched the holes up three times.
How long are running shoes supposed to last you? They are expensive! Are they expected to do this, or should they last much longer?
When I ran long distance in high school I’d replace my shoes every year, over xc and track they probably had around 800km on them, some years a bit more others less. I learned quickly that changing brands or even models from what worked for me was bad so always got the Mizuno waveriders that were available that year.
As others noted you’ll feel the midsole start that lose its cushion well before you see wear in it. Even when it looks like it has bounce, it may not be providing what you need to cushion the forces from running (a normal pace can see many times your body mass as force on your foot as you and you want to absorb a lot of that to not ruin your knees and hips).