what exactly is the benefit of having a byzantine set of standards in the first place? Like why not just have a standard and not dick around with it?
If there are things browsers can't do natively, then someone will build their own way to do it and then you end up with non-standard implementations.
It's better to get everyone on the same page and develop an open standard.
Adobe / Macromedia started from the designer perspective but Flash soon became a goal of its own because Adobe wouldn't give up that marketshare.
Only now all parties realise it's too big for one company to own. Well except Google perhaps.
Users and website creators wanted these features and Flash was the way to do them.
Sure, other technologies like Microsoft's Silverlight allowed similar things, but Flash was so widely used it could be relied on to offer these features.
Even now things like clipboard access aren't supported in the same way across all of the major browsers.
I think the disconnect was more with designers. They wanted visual tools back in those days and had no time for CSS and JavaScript. Adobe/Macromedia gave them what they wanted and also entrenched their commercial position this way (which Adobe already had in the paper publishing market!). It took a long time for the graphical guys to come on board with the open toolchains.
Macromedia wasn't a bad company as such as they did make the excellent Dreamweaver which did promote open standards, but Adobe corrupted them badly.
And I recall it enabled a progress bar, too.