Right now MSFT is trying to get corporate to switch from XP->Win7 in 3-5 years they will be looking to move Win7->Win9
There used to be corporations that were in the opposite release cycle, but Vista effectively killed that for Microsoft.
If MSFT can get everyone at home AND at work onto their services, running Office on their cloud and with all your line of business apps running on their servers.
Charging customers $100/month/user for SaaS certainly beats selling them a new $100 cdrom every 5years
These numbers don't make a bit of sense. The most expensive Office 365 plan (excluding the ones that include desktop Office) is $14/user/month. And a license for desktop Office costs a whole lot more than $100.
There was a story on here about MSFT moving the FAA users to the cloud which worked out at $71/user - and currently nobody 'pays' for for Office ;-)
With everyone now having a PC and less reason to upgrade to a new OS every 2years - the only way for MSFT to keep up revenue growth is to start charging for biz and home users for continual service stuff.