A coworker of mine that worked at Adobe through the death of flash said a big reason for that death was Apple deciding the Ipod touch Safari would not support plugins.

Adobe had big plans on the Ipod supporting Flash and that announcement all but killed their Flash division.

Yes, Adobe supported Flash for years after that, but it was more of a life support thing and not active development. They saw the writing on the wall and knew that for flash to survive, it had to survive in a mobile world.

With the decreased support of flash, the other browser devs simply followed suit and killed off a route for something like Flash running in a browser.

Makes sense, Flash was eating battery like crazy. And it was widely used in ads, so it would appear on all pages of the internet.

One of the first things I used to install on all my computers (laptops and desktops alike) was "block Flash until clicked" add-on.