OP didn’t say “little-used” software, they said “nobody,” and I think this was meant to be taken literally in this context. Software that has 0 users is of no use to anyone by definition.
If you are using quality as a metric then something having more quality would mean it having more value to more people. So a piece of software working 95% of the time to 1 mil users is deemed "of higher quality" by this metric than a piece of software working 100% of the time to 1k users. I don't think this definition for quality is good at all
You’re still missing the point: software used by LITERALLY 0 PEOPLE cannot be useful. Whether it’s well written is completely irrelevant because it, by definition, is providing value to NOBODY.
Agreed. The quality of a software package doesn't change when its last user stops using it. We don't say that the Apollo Guidance Computer software is of low quality these days given that nobody's using it.
Software quality is, roughly speaking, intrinsic to a software product. Its usefulness is not intrinsic, it can depend on any number of external factors. Quality is not the same as usefulness.
But if it’s unused then how does one measure quality? We can write all the tests, look at architecture patterns, etc. but software truly is a case of “the proof of the pudding is in the eating.”