Jobs' proposed alternative to flash, html5, did not solve the battery hogging problem, just made it move over to html5. If anything, it made it worse because you lost the quick fix of disabling flash (or rather click-to-play). That's why even iOS devices have ad blockers now, the mobile web is horrible without them.
Of course your MBP would spin its fan and drain battery when playing a flash game. But it would do the same, and faster, when playing the same game implemented in Javascript, even more so at the time.
Having my fans go on full blast because of Flash is something I remember happening quite often. Having my fans go on full blast because of html5 is not something I remember at all.
And your use of games here is a red herring. Nobody complained about games using up battery. The complaint was flash ads using up battery.
The battery argument was weak and I'm sure Jobs knew. Video was a significant chunk of flash's use case, but not the only part, and flash was much more battery efficient than HTML5 at all the other stuff it did. Even today you can't do buttery smooth flash-style animations in javascript without some major hacks (like using webgl). Even simple effects like full-screen fade-in that flash could handle on a pentium can't be done smoothly at all in CSS.