How relevant is that figure when Intel CPUs universally outperform that by leaps and bounds?

If you actually use consummer CPUs a lot (maybe e.g. you are a kernel maintainer and compile Linux all day) some of them may not last how long as you think.

Or if you put consummer CPUs in embedded equipements that are always (or at least often) under load, Intel will not care much if you have an high failure rate after a few years, even if you buy an high volume. They have dedicated SKUs with better expected durability.