Russ Cox, the tech lead for the Go programming language at Google, made a case for adding opt-out telemetry to the language's toolchain in Transparent Telemetry for Open-Source Projects.
As a former open-source maintainer of some fairly large projects, I understand the pain. Without telemetry – you're a product manager flying blind to feedback. From more complex questions: What features are getting used? What APIs are dependent on? To table-stakes questions: How many users are using this tool? Did the last release break something?
Developers often have a viscerally adverse reaction to telemetry. It represents centralization, tracking, and everything wrong with the software industry. Maybe it's just a vocal minority, but developers' revealed preference does not match their stated preference – most developers still use VSCode as their IDE, sending thousands of telemetry events per session. Likewise, Go still collects data through the Go module proxy. And there are far more examples of telemetry in popular projects – Java, C#, .NET Core, Homebrew, Debian, Ubuntu, GitLab, and many others.