[Stephen]

Insiders without genuine keys will only be able to keep a free and updated version of Windows 10 if they stay in the preview and continue to try out preview builds.

If you don't do that your Windows 10 will eventually cease to function.

Insiders that have genuine keys from Win 7/8 then they will get the RTM and any regular system updates after that, they won't have to keep testing new builds.

I see that as a good trade off For example I only use Windows via bootcamp to play games every so often and also to stream X1 games now. Its not my main OS so being able to keep it working for free is fine by me.