It isn’t even just the government, big tech wants this too. They want to be able to track everything you do with your computer, and that’s more easily achieved if OS level identification is required. Big tech wants it for data harvesting and ad targeting, the government wants it for surveillance and narrative control. The end goal is government verified digital ID that will be required to use any operating system. There will be no anonymity anymore. This creates a panopticon effect in which people police themselves because they know they are always being watched. Furthermore, the information you receive in your social media feeds and web searches can be silently curated based on what is known about your political attitudes. It can all be managed by AI.
To an extent, yes, but they could do it much more easily and accurately if there was a unique, biometric identifier associated with all your actions across your devices which cannot be disabled.