Aufait what does it give for the neuneu who bought a notebook at 250 ? with "windows 8 with bing" (which, I remind you, has a key incompatible with home and pro)?
Well they will have the free win10 upgrade the first year. And there you are talking about a percentage of the small percentage that represents win 8 / 8.1. It is peanut compared to the win7 still present on the park, sold more than 5 years ago.
They will still be able to charge licenses for new equipment the first year through the manufacturers, and then it will be a form of return to normal.
Even if they "give" Windows and seem to create a shortfall, it is probably well calculated behind and not cheap if they make sure that the OS will be quickly adopted. Stop looking to see the wolf or the NSA on every street corner. The OS market has changed, that's all. Long gone are the days when we paid a high price for Windows (like 1150Frs my 2000 pro), Microsoft has since diversified its revenues and factored players. The ultra portable technological merdasses of which you speak have a fairly high renewal rate (almost disposable like smartphones), they will be replaced in the medium term by a new model under a win10 bill. Industrialists produce kilotons of it every year and sell off stocks when it doesn't go away. Also, if they sold it (or not sold it) with 8.1, MS would not have resold the license until the next purchase anyway. It is a false problem. The recent desktops / laptops recently sold in 8.1 represent, on the other hand, the first part of this seduction operation. Regarding the config under Win7, they are generally starting to age. This donation is only a mishap, under 2-3 years a good part will be renewed. As for the retro bullet-testers (of which I am a part) which reinstall Seven on all their configs (recent or not), it is there that they extend their hand and the second cheek of the accountant, to attenuate an XP phenomenon.
The overview is quite simple. Instead of waiting for the sales of new hardware under win10 to sufficiently take off the number of users, they immediately rely on a pool of migrants who will advertise themselves as the updates free features will arrive. And if they do not miss too much on what they have announced, it will tip the rest of the park faster. The win8 / 8.1 period was not very pleasant, calls it a commercial gesture.