Not only that, but Flash isn't perfectly "cross-platform" either. It's really only a great experience on Windows and 32 bit and a crapshoot everywhere else, it'

Not only that, but Flash isn't perfectly "cross-platform" either. It's really only a great experience on Windows and 32 bit and a crapshoot everywhere else, it's still the major cause of browser crashes everywhere else, has struggled with 64 bit implementations, has a long history of sandbox security problems, and their feigned "open source" efforts where there's proprietary parts they don't document or release garners them few OSS friends, downgrades poorly, is a significant resource requirement overhead, and isn't very accessible by default (the standard swf you encounter will not be blind-user accessible). If Flash is the answer, we're in even worse shape than using HTML/JS.