I feel like Google simply didn't like users having such control over extending their browsers' functionality in ways that are harder to track, so they started the anti-flash bandwagon by abusing their browser's market share to kill it along with all other add-ons (a continuation of their death grip on what extensions are allowed and making unapproved extensions not available to the average user either), leaving a vast graveyard of significant, great content unavailable to the average web user. The golden age of web functionality was the period of HTML5 and Flash both being supported at the same time and Firefox having full support for NPAPI and the old extension system including allowing unsigned extensions. Now we're stuck suffocating in sterilized walled gardens almost everywhere we go. Android still lets you install third party apps for now at least but I bet the days of that are numbered too. Sad state of affairs for users all around.
I think Steve Jobs was more responsible for Flash's death than Google. YouTube only stopped serving Flash as the default less than 5 years ago while hubs like Newgrounds were seeing significant declines well before then.
Maybe I'm misremembering, but the golden age of Flash content was certainly over before HTML5 hit in a big way.
