Can someone explain why stalls occur in weight training?

I haven't yet gotten a clear answer on this. Maybe this belong in MM, but what the hell.

If someone eats, rests, and lifts well, what causes him or her to encounter a stall at a particular weight? And once this stall is broken past, why would progressing seem easier instead of at least as difficult? (Or is that even the case?)

I have read that a stall happens when muscle fibers and CNS capabilities are maxed out. Sounds reasonable. But then again, why would they be maxed out if I was eating and resting enough in the first place?

Let's say I was not eating and resting enough to break past a certain barrier; would my level of rest and food need to be permanently increased from here on out to make further progress?