Here's the thing. Microsoft, the money grasping bastards that they are, have never once come out and said, categorically, clearly, plainly, that after the free year (free excluding if you don't want the full range of windows accessories that you got for free with 7 and 8) it will be free forever. They have release statements that are wishy washy, not clear, and keep using the key phrase which is free "for a year". So no matter what the rest of their statement is, the critical and most consistent part of their message is that for a period of 1 year, it is free. Even in the blog released by Terry Myerson which almost goes straight to the "It's free, it will always be free until your computer dies", if you read it with eyes full of hope and trust, you might miss that he includes phrases such as "we will continue to keep it current for the supported lifetime of the device – at no cost" and then the asterisk behind "We announced that a free upgrade for Windows 10 will be made available to customers running Windows 7, Windows 8.1, and Windows Phone 8.1 who upgrade in the first year after launch.*" which takes you to "*Hardware and software requirements apply. No additional charge. Feature availability may vary by device. Some editions excluded" which says Free, except maybe not.
The other point to consider is the advertising weight of Microsoft with minor and major publications. Not many will bite the hand that feeds them and write something not condoned by Microsoft.
The reality is that the only people who know what will happen after a year is Microsoft. My experience of moving to 8.1, and all the extra "for security" measures they insisted upon which basically makes you link everything you have and do on a computer to one of their accounts I found annoying, so god knows what they will insist upon with 10. Scan of passport? Fingerprint? Retina scan? DNA swab sent to them