When comparing on a mileage basis, EVs have very similar failure rates in the early years, differing by less than a percentage point. But that changes once you get to higher mileage numbers – past 40,000 miles lifetime.
At that point, petrol cars are less reliable, and the reliability only gets worse over time. By the time a petrol car reaches 120,000 miles, it’s 7.5% more likely to have failed than an EV (16% vs. 23.5%).
It's been a long time since 40k miles was considered "high mileage". Most people use 100k as the line, and sometimes even higher.