It's not subjective at all. It's not art.

Code quality = less bugs long term.

Code quality = faster iteration and easier maintenance.

If things are bad enough it becomes borderline impossible to add features.

Users absolutely care about these things.

Okay, but I meant how you measure is subjective.

How do you measure code quality?

> Users absolutely care about these things.

No, users care about you adding new features, not in your ability to add new features or how much it cost you to add features.