It's not just developers, just like Microsoft made web applications that only worked on IE (think Outlook.com and the introduction of AJAX) we've seen it here on HN all the time, they announce new products that are only known to work on Chrome initially. Some have even changed the user agent and it works on Firefox, so there's some old school Embrace Extend Extinguish nonsense going on from Google's end when they introduce new products.
I remember that every browser had an AJAX API, where IE had a specific API that was more straightforward. The AJAX capability was a forgone conclusion rather than a technical leapfrog. You could always had access to an HTML request and timers to code AJAX as a final backup.
