The huge advantage of Flash is that it works, looks, and behaves exactly the same across browsers and platforms. There is nothing else like that available. HTML5 is seen by browser makers as a friendly recommendation allowing for partial support and browser specific code (lately especially with Chrome which turns into the new "IE-only" browser). HTML5 also only prescribes the markup and the intended outcome, but not how content is to be rendered. Look at a page in Firefox, Chrome, IE, Opera, Safari, etc and the same page with the same HTML5 markup looks different in each browser and might not behave the same or work at all.
Rather than call for the death of Flash let's fix it...or come up with a true cross-browser, cross-platform alternative that is not dependent on the good will and immune to the arrogance of browser makers.