Do they do tear-downs and rate the engineering? That's pretty much the only way to determine how likey something is to last without using it for ten years.
I don't think they do tear-downs but they do stress test them extensively. Their reports also include their testing methods in detail. For washing machine testing, for example, they independently bought 3 of each model and ran each through 1840 cycles. That's equivalent to 3.5 cycles per week for 10 years. They checked how the machine held up in comparison to the beginning and if any repairs were needed.