That may be the case, but the last few pairs of "normal" shoes I bought had to be discarded after a year or so, not sure if the sole was still ok, but it didn't

That may be the case, but the last few pairs of "normal" shoes I bought had to be discarded after a year or so, not sure if the sole was still ok, but it didn't matter: they were done and because of their construction you couldn't fix them. My last pair of quality leather shoes held up nicely for about three years and it's now relegated to construction and garden work. My current pair is spotless after two years. The soles on these are synthetic, but they degrade about as quickly as the tops. Not sure where you draw your experience from, they don't match with mine. EDITED TO ADD: Of course quality shoes can be refurbished with new soles, so even if a leather sole would only last a couple of years, you could simply get a new sole slapped on.