Expert Witnesses are often paid eye watering sums of money

One of my professors was an expert witness on cases related to CPU cache design IP. He got paid $1000/hr. He said the opposing side would pick through every past resume he had looking for anything incorrect, and would interview his former co-workers and even neighbors I think looking for dirt on him.

Since Amazon is making the request, they pay:

Rule 26(b)(4)(E) Payment. Unless manifest injustice would result, the court must require that the party seeking discovery:

(i) pay the expert a reasonable fee for time spent in responding to discovery