There's many sides to this.
Even Boeing doesn't value clean code (as shown by the 737 MAX disaster where 9$/h coders were hired in India). So you can imagine how much a local non-tech company values clean code.
There's also that a lot of these companies simply... couldn't recognize clean code even if they saw it! Since they aren't competitive with top players, the caliber of programmers they attract is nowhere near the level of engineers at real tech companies. Unless these companies "luck out" with an extremely high caliber hire, they won't really know there's a better way of doing things [0]. Think places where source control is still seen as too complicated or not needed.
[0] https://www.hanselman.com/blog/dark-matter-developers-the-un...