> Say what you will about a lot of the garbage in player, the authoring tools were some of the best available...
I emphatically agree. Back in 2004-2006 I was doing Macromedia Flash MX 2004 development (with the new-and-shiny ActionScript 2.0! Based on the forthcoming ECMAScript 4 standard that should be finalized any day now...). It was hands-down one of the best development environments I've used w.r.t. creating games and "rich Web applications". It really was the best thing available at the time: you could draw and animate your sprites, tiles, backgrounds, whatever within the same IDE in which you wrote your code. You could attach scripts to any object on- or off-stage, and they ran in an event loop. The documentation it shipped with was also excellent, and I picked up a hardcopy of the "ActionScript 2.0 Bible", a massive tome of beginner's tutorials, intermediate tips and tricks, and complete language and library reference -- for a measly $20.
Nowadays, Unity gives a similar yet more featureful environment for writing games, and Silverlight briefly presented an alternative for "rich content". As far as rich content goes: sure, we can do that stuff with HTML5 and JavaScript nowadays, but it was just so much more pleasurable to work with the Flash IDE than anything else I've seen, excepting maybe Silverlight. Where making a Web 2.0 application feels like an enormous pain in the ass, making the same in Flash was a joy. It was fun rather than frustrating!
I think if Adobe (or even Macromedia) had opened up the Flash format (SWF), and maybe even the plugins, things would've gone a lot differently. Flash could've been a law-abiding citizen of the "Open Web", and we could've seen some healthy competition amongst development and runtime environments. The community at large could've found ways to iterate and improve on the technology. But, I suppose that ship has sailed and we're stuck trying to jackhammer the round peg that is application delivery into the trapezoidal hole that is document delivery (i.e., the Web).