In the article they cite the MBP as being the most popular notebook for developers so this niche must be important, otherwise why list it? That "most popular"

In the article they cite the MBP as being the most popular notebook for developers so this niche must be important, otherwise why list it? That "most popular" is marketing - they have all of the developers running OSX and most of those are probably on MBP or Air, where developers using Windows or Linux are fragmented across multiple models from multiple manufacturers.