You say:
> The GPL is a good fit for open source users
As the thread tells you, it's clearly not for the many Apache/MIT licensed Rust projects that cannot use your GPL licensed code.
Again you say:
> With the GPL, we are happy to let open source users use the library for free. Commercial users still will be able to use the library because of the escape hatch of the dual license.
You make this differentiation between commercial and open source users while conveniently ignoring that the most permissively open source projects (Apache/MIT) are practically prevented from using your software.
At least with BSL, projects are honest about what they're doing. Don't play both sides.