Great engineering is not maths -- it involves tradeoffs, wisdom and experience... The company puts such a premium on independent groups working fast and making their own decisions it requires a particular skillset, which generally involves a great deal of field experience. A related trend is hiring seasoned marketing talent from the likes of IBM. Some other older companies have older distinguished engineers because they grew up with the company. AWS is explicitly bringing that experience in. It's refreshing to the see a different perspective on value.
In a later post the analyst acknowledges engineering managers are generally older than their reports, but adds that "If AWS sees value in hiring engineering leadership from folks that are frankly a bit older than the norm in the industry, isn't that worth shining a light on?" In response to the article, XML inventor Tim Bray suggested a new acronym: GaaS. "Geezers as a service," while Amazon CTO Werner Vogels tweeted "There is no compression algorithm for experience."