When consumers say they care about the internals of their cars, what they actually care about are things like power, fuel efficiency, torque, whatever. They have nothing more than a superficial understanding of how the actual mechanics of the vehicle translate into these qualities. Talking about V8 engines, etc, is, for the typical consumer, nothing more than marketing.
HTML5 could certainly be a marketing device (5? That's one more than 4, it must be better!), especially if you showed end users cool things that web sites can do with HTML5 that they can't do with 4.
edit: ultimately we'll probably need some numbers to back our claims. I've got way too many bugs to fix to do any significant digging. But I'm open to counterexamples if you can find some numbers.