> What sort of metric would I have registered as?

Monthly average user. Uptime for Win 11. Uptime not counting screensaver. Uptime for non-enterprise consumer. If you were a Win 11 enterprise user, then Uptime for enterprise users. Unique hardware indicators - number of distinct PCs in Win 11 ecosystem, separated from new activations. And I'm sure a few others that I haven't thought of.

Declining stats on these measures indicate a problem somewhere in the Win 11 ecosystem. Combine with competitor indicators like sales, and other Win ecosystem OSes.

A single person switching probably doesn't do much to move the indicators. But as a collective?

If a decent number of people migrate away, it would definitely show up in aggregate: Windows Update traffic, for example. Or sales of Windows-specific software/subscriptions. It doesn't require correlated tracking at an individual customer level to see the broader trend.

Losing market share to ChromeOS and Apple has to be the most significant and obvious hit. The Steam Deck and second generation Steam Machines are also likely to nibble away at the edges.

I am not a Mac person, I actually hate a lot of how they operate. Yet, if a tech-illiterate friend were looking for advice, I would likely steer them towards those computer appliances so as to avoid Microsoft's nonsense.