As much as I want people to stop using Flash for new projects, I'm worried what this means for preservation. There are a lot of old Flash games and other stuff out there that has never been ported to HTML5 and have been abandoned by their creators. A decade from now, we're probably going to need to run an old OS in a VM just to run this old content.
We're at risk of a digital dark age already, and this is just going to make it worse.