Flash went away because Steve Jobs made an impassioned plea to find a better way and follow their humble browser which only had single digit percentages of marketshare at the time.

Even for enthusiastic Android vendors who saw it as a differentiating feature from iPhone, Flash still took three years from the iPhone launch to have its first release. Adobe was really in poor shape to port Flash to a new platform. Waiting for them as a vendor to bump their proprietary platform vs integrating support for the features into the browser would have cost years for mobile adoption.

html5 canvas and javascript advancements made flash obsolete, reminder that you used to be able to run java in the browser!