You're telling me that people who want to replace a command-line utility are the same people who can't install a toolchain (or just download a binary and put it in their path)?
As a single-sample statistic I can share with you, I like to think I'm a well seasoned C/C++ developer, and have experience with all sorts of relatively low-level technical stuff and a good grasp on the internals of how things (like e.g. the kernel) work.
Yet I got confused the first time ever some README told me to run "npm install blah". WTF is NPM? I didn't care, really, I just wanted to use blah. Conversely, later I worked with Node devs who would not know where to even start if I asked them to install a C++ toolchain.
The point is don't assume too much about the background of the people reading your instructions. They don't have in their heads the same stuff you take for granted.
Don't focus on the specifics, consider the NPM thing an analogy for any other piece of software.
I've found instances where some documentation instructions pointed to run Maven, and the commands worked in their machine because Maven is highly dependent on customizations and local cache. But it failed in other machines that didn't have this parameter configured, or that package version cached locally. And trust me, Maven can be _very_ obtuse and hard to troubleshoot, too much implicit magic happening.
Testing in a clean container or VM would have raised those issues before the readme was written and published. Hence my point stands, testing commands in a clean system is akin to testing a web page in a private tab, to prevent any previous local state polluting the test.
Testing in a clean container tests deploying in a clean container. For me, I run a computer :) Maven sounds like a nightmare tbh so I can understand that that specific piece of software has warts. That said, a good piece of package management software will be relatively agnostic to where its run and have a dependable set of behaviours. I much prefer that to a world where every bit of software is run on any conceivable combination of OS and hardware. What an absolute drain on brain space and creative effort!
