Jobs is right, when using laptops I notice the operation of the fan and very often a web page with Flash in it single handedly uses enough CPU to heat up the device so that the fan kicks in. Undoubtably this sucks battery and there's nothing I hate more than a portable device that goes flat too soon.
The effect on memory and CPU of using Flash can be simply seen by comparing memory use on the Flash or HTML5 version of YouTube.
And here's the HTML5 version:
So 76.9MB to play flash compared to 53.9MB using HTML5. A total of 37.7% CPU for Flash, compared to 10.3% for HTML5. Hardware acceleration of H.264 video promises to further reduce CPU and power consumption in the future.
The thing that Flash has is mature development tools. Recently I've been using the animation effects in jQuery and they look very smooth. What's needed is a tool to construct animations that play in the modern browser.
Step one is for manufacturers of potentially very popular devices, like Apple with the iPad, to have the guts to not allow Flash on there. Once major site builders see their site littered with little lego bricks they'll have to start getting by without flash.
I choose battery life, stability and standards over Flash any day. Only Apple and Google (YouTube) have the power to pull this off, I support them.