>You can send a link to your mom and she can just play it w/ no issues
Is this an argument against IE? If so then the pain of installing flash wouldn't be "no issues". If we're assuming mom used chrome here then what's the argument against HTML5?
Packaged apps were (discontinued) also more accessible than an SWF file IMO. Rather than explain how to find/run an a file it was just there to click in the browser.
I wouldn't say javascript serves a useful purpose anymore as it's being used to generate entire UIs. It's more a requirement, and performance is taking the heat.