The major components of Flash are a vector graphics engine, a timeline based video editor, and a scripting language. Leaning on browser SVG support and exec(),

The major components of Flash are a vector graphics engine, a timeline based video editor, and a scripting language. Leaning on browser SVG support and exec(), you could write an extremely bare-bones version in a couple of weekends. It'd be a great open source project. As a commercial product, it'd probably be enough to support a small team, but I don't see a way for it to get huge.