HTML5 has potential to make good games
Oh it's definitely possible, my point is that Flash currently has a lot of good tools for making them which makes it much easier over all, especially for hobbyists. By comparison, HTML5 is only really now making it possible for games to compete, but the tools aren't there yet to fully support them to the same degree, which means there's a lot more grunt work to do until more libraries are developed for people to take advantage of.
Personally, what I think would be most interesting would be if Adobe worked on positioning Flash (the editor) as a means of building HTML5 content, and provide the libraries to support it. I mean, HTML5 lacks the kind of easy vector support of Flash, and ActionScript is essentially a language designed to be interpreted into Javascript anyway.
If this meant that Flash sites could convert their content into HTML5 at the push of a button, and still enjoy the same ease of creation, and avoid loosing time invested in learning Flash (or acquiring people who know it), then Adobe could easily allow Flash to survive. After all, the Flash platform has always been free, it's the editor that Adobe makes their money from, so retooling the Flash editor to build HTML5 with Flash libraries would allow the Flash and Flex to survive quite handily.