It might be acceptable if Microsoft gave their product away for free: many free products (e.g. Sublime or Skype) include annoying autoupdate popups for non-paying users. But Windows is quite expensive software.
Microsoft's motives are just getting more paid services, getting more telemetry (for free! they do not pay for it) and maybe adding some kind of subscription in future. Recent Windows versions like 7 or 8 seem to be 'good enough' for most customers so they do not want to upgrade for free let alone buy newer versions.
And subscription is as bad as DRM.