There are lots of IC cars that have done a million miles on one engine...half a million isn't even noteworthy. Forget about it with diesel engines, very common. Reality is electrical drive units actually seem less durable than a typical IC engine, common to see them replaced with 50-60k miles on them and under.
I read the Tesla forums all the time, their maintenance issues are legend. Quality is lacking when they are built and then try to get repairs and parts done in a timely manner, a nightmare. When the likes of VW and others get serious about EV's Tesla will be no more. Scale matters in the automobile industry. It's already showing up in the sales numbers. Somewhere in here Tesla is a short for those willing to step in.
Ford's Q3 China sales were 164,000,
GM Q3 China sales were 774,000.
Tesla Q3 China sales were 34,000.