Anyone who has seen Flash animations/games/puzzles/quizzes/videos on the early Web [or by opening downloaded .swf files directly inside Internet Explorer] knows that that kind of interactivity is missing from today's Web, despite staggering advancement in Web standards/technologies. There are not some but many things that just can't be done [today] without Flash. And in some ways the Web was more "alive" and interactive in the yesteryear than it is today [with the keyword being "in some ways"], all thanks to Adobe/Macromedia Flash.
Battery life, security, performance, memory usage, etc., are just excuses [all of these can easily be corrected by optimizing Flash Player]. Flash is being brutally murdered because it is so great. It gives Adobe the power and the direction. It enables platform independence [like Java], something that neither Apple nor Google wants [two of the biggest anti-Flash companies, unsurprisingly]. It's not easy to put ads inside Flash applications, hence Google sees Flash as its big enemy. And so on.
Despite all this, us folks who've seen its true power know what Flash is.