I was in the same situation a couple of years ago. I had over 15 years of experience, was invited for a technical interview at Amazon, and failed. At first I was irritated, just like the author. But then I decided to turn this negative energy into something positive and followed a couple of courses on Algorithms on Coursera, also I discovered Hackerrank. And I found out that I actually loved solving algorithmic problems!

Now it is a couple of years later and I actually was able to land a job thanks to my new skills (not at Amazon though). But what's much more important: I found a new hobby that will keep me entertained for many more years.