The problem is that most public aquaria rather buy fully grown specimen than growing them from juveniles. It's too much driven by what the public likes to see and not enough by how it would be done right (they could also grow a complete reef if they wanted).
Also they get some fish from donations (fish that got too big for home reef tanks).
So while I think a tank like the big one at Steinhart in SF would get them to grow to full size quickly, I doubt the ones they have in there actually grew to their sizes there.