I wouldn't put an .envrc file in source control. This seems like an anti-pattern.

I think it should be standard practice that you can pull and run a project without configuring environment variables. I agree with that. The defaults should work.

This is not always possible (when you have something that absolutely relies on a third party thing, which you need an environment variable for) - in which case you should be greeted with a helpful error telling you what environment variables you need to set up and why.