Its just not that simple.
You can have over 11 volts but if the ratio of depleted reserves in amp/hours is large enough combined with the continued stereo draw that is large enough the voltage will drop like a rock and the Blue Sea will open again. This isn't a problem for minor systems but is a real world challenge with BIG systems when you cross a threshold in stereo size and stereo battery bank reserves.
Having 200 amp/hours at 80 percent (11.5 volts) depletion is far more challenging than having 65 amp/hours at 100 percent (10.5 volts) depletion. Its more an issue of current versus voltage. Voltage is just the consequence.
Seriously depleted batteries can be a real liability to the charging system and the ACR/VSR operation.
Like I said its complex and a moving target as systems become larger.

Earmark Marine