@restorer-john makes a good point in the Rolls Royce engine comparison. World-class products use world-class materials and components almost without exception. The analogy to some hifi gear is fair, especially for some of the vintage stuff.
@March Audio makes a good point too; you don't need to exceed your own specifications, and it would be a waste of money to do so.
An aerospace company has specs that require top-end components proven out by rigorous testing, usually of every batch, down to the screws. A military helicopter radio that sounds like a cheap AM radio can cost $30k (or more), but it will probably be reliable, and it will definitely have good components.
I don't have a big problem with say and NC400 module being essentially disposable at its price, but I don't have any illusion it is Rockwell Collins. I don't have any illusion it is TOTL hifi either. I think of the whole module as a replaceable component.
I agree, in a $2k+ amp, I would want good caps too, and I wouldn't buy this. I would buy a less expensive stereo NC400 or something similar though.