I said my windows 7 key didnt become deactivated. No time travel needed
So basically the win7 key I used to upgrade my win10 test machine still works if I use it on a new install and activate.
Windows 10 isnt aweful, my main reason for not using it is the enforce rapid development model, on all my production machines I manage my updates via komms update checker which installs all hotfixes not just windows updates, I like the ability to keep certian updates not installed and upgrade at my own pace. I also value a stable UI.
On my windows 10 test machine, everytime there is a new build (update that requires OS reinstall) apps break, notably security apps and 7 taskbar tweaker. Then there is a time lag before these apps get fixes to catch up. Sometimes core windows functions break as well e.g. hyperv was broken for me between RTM and TH2. The policy editor trick to set update to notify only is ok, it adds a degree of control back, but its not the same as win 8.1 and 7.
Funny enough it turns out DX12 is actually a bit of a hindrance as microsoft have tied that to the universal apps code, meaning DX12 stuff uses microsoft store API's and various functions gamers are used to in game dont work as well such as controlling vsync. So with me not currently been bothered by DX12, I dont think win10 has a single feature I crave for. Of course this may change over time but I am ok for now on 8.1.
I am now glad I upgraded from win7 tho, as I discovered the newer WDDM model in 8.1 works much better for gaming, the appcontainer is a good security improvement and I like the start screen as a good idle screen showing status of weather etc. I used my 2 licenses I brought for win8 when it was released on the cheap upgrade offer they had (was about 10gbp each). Secureboot is also a very good security improvement to protect from malware bootloaders.
Back on topic, remember the pricing revealed is scaremongering, oem keys for windows 10 will likely be available on key sites for very low prices (sub 20GBP) and microsoft themselves will very likely pull out some kind of offer, as they still want people to switch.