In restaurant kitchens, during service, ovens are mainly used for finishing, so food only spends a little time there (if at all). Often, a salamander is used to quickly broil. So, the oven, as you understand it, is more often a prep. tool, used when there is more time to stagger prep. or allow for more lengthy preparations. For something like baked fish (which doesn't take all that long), cooks just share the space among orders. As @Chris H suggests, the oven remains hot through service. Precise temperature control is really not an issue. It is more about timing and workflow.

In restaurant kitchens, during service, ovens are mainly used for finishing, so food only spends a little time there (if at all). Often, a salamander is used to quickly broil. So, the oven, as you understand it, is more often a prep. tool, used when there is more time to stagger prep. or allow for more lengthy preparations. For something like baked fish (which doesn't take all that long), cooks just share the space among orders. As @Chris H suggests, the oven (and frequently a convection or combi-oven) remains hot through service. Precise temperature control is really not an issue. It is more about timing and workflow.