Exactly this. It's all done ahead of time. The grill cook only has to throw it on the grill, sear it, warming it up enough to eat, but making sure the interior doesn't go above whatever the original sous vide temperature was.
> I mean a real steakhouse, not a family restaurant masquerading as a steakhouse
Exactly. Outback and Chilis has awful steak, but that explains the steak cooking advice here. Mortons is probably the best chain restaurant steak in the US. Texas Roadhouse for a cheaper almost-as-good version, but still far and away better than Outback