Sorry but this is simply not true. After a while we decided to do exactly the thing that the article describes as our preliminary interviewing process at Amazon. We also had extensive onsite interviews, however we did not ask candidates to code at the whiteboard. Btw, when you work for such companies it is expected that you spend 10% of your time on hiring. Getting hiring right is one of the most important things that you need to do at the scale of Amazon, Google and all of these large companies. Having a single bad hire can bring down the performance of an entire team.