1) What are some factors described by the research mentioned in the article that drive increases in pay differences over the past several decades?

2) Excluding the firms mentioned in the article, describe a company that has increasingly focused on a narrow set of core competencies.

https://www.nytimes.com/2017/09/03/upshot/to-understand-rising-inequality-consider-the-janitors-at-two-top-companies-then-and-now.html?mcubz=0