It was done to gather market share... get everyone on Win 10 and drop support for older Win OS's. One OS to rule them all
Looks good at the stock market also.
I upgraded 3 machines, still 2 older laptops on Win 7, and I have one Retail Win 7 Pro just incase I need it.
Still need to get a MSDN sub for everything else I do. TechNet was a good deal, sad they got rid of it.
After the mistake of Win 8 I don't think many would have purchased Win 10, forcing people to purchase new OS never goes well and becomes slow in adoption even if it is a good upgrade. So doing it free really pulled in a lot of people. I also like getting rid of support for older OS, it makes keeping the new OS much easier to keep current. Do we really need XP anymore ?
I also don't mind the update system Win 10 uses. So many machines I have worked on had no updates on 7 and XP machines, people just didn't do it and ended up with machines so full of malware, its better for them to have it done automatically really. All of us here are an exception of course
I do think XP and Win 7 are still going to be around for a long time, playing new games and software may not support these. But that was going to happen anyway when moving to new Directx's and GPU drivers. Ubuntu is just a pain IMO, I just do not like having to compile everything I want to install plus if you are a gamer you have very little choices out there for stuff that can run on Linux.