This doesn't appear to have anything to do with how long free updates are provided; rather the issue is how revenue is recognized from sales of Windows 10 which

This doesn't appear to have anything to do with how long free updates are provided; rather the issue is how revenue is recognized from sales of Windows 10 which are actually bought. The source presentation doesn't appear to apply to the free upgrades at all -- only new revenue -- so both Forbes and CW are reading too far between the lines here. The majority of consumer Windows licenses are OEM bundled with a a new PC (which cannot be transferred to different hardware). Given the new update model, that Windows purchase is now closer to a "subscription" purchase of indeterminate length, instead of a one-off purchase, so deferred revenue recognition over the expected length of the "subscription" period makes sense. As licenses are tied to the hardware, that "subscription" length is the expected device lifetime, which varies by device type. There's no information there one way or another as to whether Microsoft plans to continue to extract revenue from devices which last longer than expected, or if they will clamp down on transferring non-OEM licenses to new hardware.