HTML 5 is still a few years out from being widely accepted and there are very few development programs available right now. Adobe is working on a major update for Flash’s backbone, AS4 which will make it more friendly to mobile devices. I wouldn’t count Flash out. Adobe is too engrained to be left by the wayside. It is also going to take many years for Flash to be replaced, if it is, which means if you buy a tablet tomorrow, are you really wanting to wait three or more years to view and work with some sites?
I can do everything I need to do on a tablet device on my iPad. Flash be damned - I don’t do anything on it that needs Flash. The “no Flash” issue is one manufactured by marketing hype, and kept alive by those bigoted against anything with an Apple name on it.
If you are curious about how well your browser and computer support HTML5 video, you can go to Youtube's HTML5 trial page and opt in (or out). If you are in the trial, most or all of your Youtube videos will be served in HTML5 WebM/VP8/Vorbis format instead of Flash.
Over the past year or so, Youtube has been in the process of transcoding their H.264 videos to VP8/WebM format (Flash needs H.264; HTML5 uses VP8). It's a big job. Youtube gets about six years a day in uploads, but the load is uneven, so they use their servers for the conversion job during the lighter dayparts.
Taking Flash and Adobe out of the web ecosystem will be a worthwhile improvement. Simpler is always better.
True, but all modern browsers support HTML5. I know Chrome does, Firefox does and the latest version of IE does.