I think the case with embedded code on crates.io is more along the opposite: they're trying to make the experience as consistent as possible by defining common

I think the case with embedded code on crates.io is more along the opposite: they're trying to make the experience as consistent as possible by defining common interfaces for embedded drivers so code can run consistently with different hardware or libraries. The problem is it's really hard to design such abstractions, especially safely, when you can't make many assumptions about the hardware it'll be abstracting over and efficiency is paramount.