Unfortunately education cannot test that, because tests are by definition testing only a fragment of a system. Knowing and understanding one thing end-to-end is meaningful knowledge, and qualitatively better than knowing fragments of 100 things. Perhaps you can assess the former by grading a diploma thesis on a very specific subject. Tests may have an important role in motivating students to delve more deeply in subjects but they don't go beyond that.
There's similarly more value to knowing some technology "end-to-end" rather than specializing in only one level and never understanding what's below.
It's also interesting to read this:
> There are now ways to get rich by doing good work, and that's part of the reason people are so much more excited about getting rich than they used to be.
Which may reflect how things were 15 years ago. There were 2 threads in "Ask HN" last week which basically concluded that these days you're much better off (money wise) working for an uncreative role in FANG.