This is pretty funny
Sorry but you are quite off bases, facebook still struggles to become overly profitable, their bottom line ends up being dangerously low all the time. Not to mention with EU fighting them over privacy, they could be forced to lose even more revenue options. Not to mention while overly popular, and they have bought a few companies out to get to their engineers they don't offer much beyond a database and a user interface to access it. Now granted they have gotten huge off the backs of 3rd party developers which reap the social aspects, but facebook as an individual entity has little more than a CMS where everyone gets their own portal. Nothing new or cutting edge at all.
Now Google has impressive abilities, and while they lost 1 person to facebook oh noes, and Google wants to start its own social aspect, aka like everyone is doing. Doesn't mean facebook / google are the "end all"
Also to claim Windows 7 was not a signifigant update / change in OS is a blinded look, it moved windows OS into full touch screen design. Windows 7 is built from the ground up to be touch screen friendly. That is a pretty big shift, not to mention the back end addition of powershell, and home network are huge pieces of windows 7 that companies are starting to utilize. I won't go into the details, but they are big for work at home people. A new driving trend in business that windows 7 was built to assist / support.
Now I do agree things are going to the web, but Google is just a new player, Apple has shot itself in the foot in regards to web, so we will leave them on the side line, but Google doesn't make web development languages, the make their add on language for chrome, but they don't create the backbone of the web. Now they do provide android developer kit, but once again you can't go and build a standalone webpage with it. So you are forgetting about the open source products, and microsofts web development tools, which as of this week, went even further into simplicity and market appeal with razor and webmatrix. Microsoft has probably spent more money into the web than Google and Facebook will only ever dream about putting towards it.
Lets face it the real battle is going to be Google vs Microsoft and everything else will just be hanging on and picking up the scraps. Now at the current moment there are some front runners Apple, Facebook, etc but being new to their respected areas is starting to show as they run into regulators, privacy advocates, anti-trust cases, etc Google and MS are well / better versed in dealing / working around those issues, and have products to support them if they get shut down on one aspect. Think about what happens to Facebook if Europe officials fine and prevent Facebook from sharing any profile information, cause it may contain information about a person that has never used Facebook, poof Facebook loses profit options for Europe, till they can rebuild their core system, and rework how information is shared. Even at that point it will become significantly difficult to provide the information vendors want to buy.