The quality of anything is proportional to the time people spend paying attention to quality measures they care about. If you care about the quality of the code (and I am extremely bimodal about when I do and do not), then spending time looking at the code, whether said code is written by a clanker or a coworker, will lead to tinkering with and improving it. If you care about UI functionality, and you spend time tweaking the UI functionality, then it will get better. If you care about performance, and you spend time measuring, displaying, improving, it will get better.

Clanker code is no exception. Slop is slop because it's low effort.

There are projects I've put most of my career into (necessarily pre-AI), and those I definitely care about the code quality. I look at every line and I don't take clanker code without going around the mill a few times with it. There are lots of things in the code I like and things I don't like and want to refactor. I care about the code quality. But there are projects I've put only weeks or month into, and some only minutes. For most of my vibe-coded projects, I've only cursorily glanced at the code. For these projects I don't care about code quality as much as the architecture and interaction. The ones where I consistently tweak it to work how I want are...just better.