Of course customers do not care about code quality in and of itself. Just like they don't inherently care about the type of seam used for a garment. But they do

Of course customers do not care about code quality in and of itself. Just like they don't inherently care about the type of seam used for a garment. But they do care if their clothes fall apart after two washes. People care if software is buggy or slow or becomes harder to use or more expensive over time. And the way we know how to mitigate that is by ensuring code quality (it's definitely not the only factor, but an important one).