[cleancoder0]

There was an explicit mention of protein quality and bioavailability. Both terms are standard and widely used. If OP meant something different by these terms, then fine. There's a minor loss of protein that is trapped in fibre for most plant foods that humans eat.

There is small amount of fiber in tofu, seitan, tempeh or other soy derivatives.

The "protein concentration" was mentioned together with iron, as if it is a problem of deficiency, not in the context of obsessive compulsive dieting by tweaking your macros to achieve the best results.

I am not sure the fiber budget you mention is a reality. There is no threshold where your body will stop behaving if you consume too much fiber.

[humanrebar]

Some people have significant health problems if they eat to much fiber. They are literally on a low fiber diet as a medical matter.

The rest of us have lower GI problems of some sort if we go too much over the daily recommended amount. That can cause significant practical and social problems. But you are correct that we probably won't die. It could be painful in some cases, though, and that would be enough.