The problem with opt-in telemetry is that 95% of users don't change defaults, and the 5% who do are your power users. They're not representative of the average user. And only a subset of them will turn it on
Ironically enough the opposite happens with opt-out telemetry, for the same reason: a lot of power users will turn off telemetry, thus you will never see their usage patterns and will have to infer them. Dogfooding helps.
If Charmin put sensors in toilet paper rolls to optimize the wiping experience, it would be dystopian. Why do we give software a pass? Privacy is a right not a telemetry problem and opt-out by default is non-consensual surveillance.
The problem with opt-in telemetry is that 95% of users are sick and tired of being spied on with every little thing they do.
I'm confused.
You claim power users opt in to telemetry, and then immediately say power users opt out.