Hmm ... really, a £200 washing machine is vastly more reliable than a lot of these pos motors. #factI saw a bunch of reports Yamaha motors did well over 10k miles and kept going. But yeah, I can't remember a single report for such high mileage for another brands motors.
10k is quite high mileage for an average and the most common emtb user, so most manufacturers do not care to design more reliable motors, but they are mostly focused on weight to power ratio, weight savings, noise reduction etc because of most people focused on those perameters when they are on the market for a new emtb and people keep believing all emtb motors are reliable enough which is not true. Most of the motors reliable enough to make profit for manufacturers, but most of them are not reliable enough to overcome 10k miles under intensive usage.
Yamaha selling point is reliability, and they can do well over 10k miles easily, but there is a cost - Yamaha motors are a few hundred grams heavier than another brands motors with comparable performance, and they are not the quietest motors.