My experience is Windows 10 gets activated whatever you do with it. If you get a new PC, you will have to pay whatever charges Microsoft decides after July 2016 for that new Windows 10 PC. So even though it says RETAIL, effectively a real transferable product key (Windows 7) does get converted to OEM Windows 10 (product key tied to that PC only for activation).

If you make radical changes to hardware or get a new PC, that Windows 10 license or product key cannot be used because it just won’t activate (because it will not recognize the digital entitlement). For Windows 10, what slmgr.vbs shows is irrelevant because as per new Microsoft licensing rules, the “free upgrade” which is called Digital Entitlement is only supported on that same PC. OEM meant that the same key couldn’t be used on another PC. For Windows 7, Retail product key meant that the activation server allowed a change of hardware thus allowing the same copy to be activated on another machine if not done within a short period of time. What the slmgr.vbs script reports as Retail or OEM is related to the way activation of Windows is handled by Microsoft’s servers.

Windows 10 retail