There has (understandably) been a lot of push back against a subscription model but this made me think about what the problem is.
When W8 was first launched there was an offer for early adopters.
I obtained a couple of W8 Pro 64 bit keys for around £25 UKP a pop (using a 64 bit W7 system).
This (along with help from online fora) enabled me to upgrade a couple of 32 bit Vista systems to a better 64 bit OS and get another few productive years out of the hardware.
I didn't feel that I had been robbed.
It seemed (and still seems) a good deal.
So a subscription of £10 UKP per year per system (I have 4 Windows systems on the go at the
moment) is not going to make a dent in the grocery bill. In the great scheme of things it is a trivial amount.
People must pay more for Pro versions of software and I think a lot of people hapilly pay more for anti-virus which gets bundled with new systems.
People also pay for new peripherals with a short shelf life - for example Wifi dongles - without too much angst.
For me the issue is trust - once in the model what happens if the price starts to climb? Can I get off the escalator without losing my systems?
IMHO Microsoft could defuse a lot of hostility if they published and guaranteed reasonable Ts&Cs.
They might even get a lot of people to migrate from XP with the right deal.
The subscription model works well for a lot of industries, not least by stabilising cash flow.
All you need is to be able to trust Microsoft.