I agree, it’s not going to hurt Google much. Remember though, Google own Doubleclick and their entire toolchain revolves around Flash. It would be quite tricky to get all of the ad creators to drop Flash and move to whatever is the most suitable replacement. Also, as you say, HTML5 isn’t here yet (and probably won’t be for a while) so the replacement options are pretty bad. Animated GIF? No rollover events, no expansions, no interactivity. HTML+JS? The overhead won’t be acceptable to publishers and the performance will suck on older browsers. Right now, Flash is the only game in town for non-text advertising and moving off it would be an extremely painful experience for the advertising industry.

Yes, it’s true that Adobe don’t make any money on the Flash Player. They make a ton of money on the authoring tools though. If Flash Player (loss maker) goes away, so does Flash (profit maker).

If you’re interested in the background of Flash, this is a great post by John Nack from Adobe. It’s important to remember that Adobe make _no_ money from the Flash player, if HTML5 offered everything the Flash player did, they could stop spending all that money on it, and just create authoring tools for HTML5. HTML5, despite all the fuss, isn’t supported by IE, which makes it very hard to take seriously in the short-term.
http://blogs.adobe.com/jnack/2010/01/sympathy_for_the_devil.html

Of course, there’s the other reason they’d attack Flash. They’ve seen how much money Adobe has extracted from the Mac-using demographic over the years and they want a slice of that. They’ve been moving into Adobe’s space for a few years now with products like Aperture and Final Cut Studio. More than half of Adobe’s revenue comes from their creative products and I’d imagine Flash is a decent earner for them.