It's more about cheap parts - low quality alloys and such will wear at a much higher rate. I killed a Hope cassette in 3 weeks (yes, actually), for example, but

It's more about cheap parts - low quality alloys and such will wear at a much higher rate. I killed a Hope cassette in 3 weeks (yes, actually), for example, but a high-end SRAM cassette has lasted me 2 full seasons. So in some ways, the higher-end stuff can last a very long time. Some brands (eg: Campy) provide for much better mid-level gear than others (SRAM), but it really depends on the model and the year. Old mid-tier Shimano gear (stx-rc / lx) used to last forever and be a very decent value offering, but times have changed somewhat. Luckily the prevalence of eBikes is making strong and reliable gear available for us non-eBikers.