

I think the truth of it is, good sound engineering costs money, time, or both. I both ran sound and did sound design for local stage theater and I was shocked at how little the designers knew how to make their transitions seamless and avoid clipping, resonant frequencies, static, and a whole mess of other issues, many of which need fixes during recording rather than post.
It took me about 5 years working with audio software before I was making stuff for other people but a lot of other people have the confidence to learn their skill working with live projects, project result be damned. I go back and listen to my early stuff and I hear all sorts of mistakes I didn’t even know I was making.
Access to good hardware/software can also be a major detriment. I’ve had to sacrifice many design ideas due to available tools. When at the end of the day, it comes down to bad audio vs no audio at all, there’s an obvious winner.
You’re specifically asking about B-Movies here. They’ll grab whoever the heck fills the chair.
If it sounds good enough for the story to be told and trick someone into watching it, the goal was achieved. Time for the next movie!
Most of the time, if the dialog is delivered and actors are on set, that’s really all that matters for tax purposes.