Or maybe they hire the best engineers who interview well? Being a great engineer and being a great interviewer aren't necessarily mutually exclusive. You can be both.

Also, after 20+ years in business, google engineers are still highly respected and sought after by every company for their tech expertise. If google didn't hire the best, that luster would have faded a long time ago.

Google has always been great at tech and poor at customer service. Though that seems to be a industry wide problem, rather than a google specific one.