Cages ought to be reserved for people who cannot be trusted to live amongst the populace -- violent criminals, habitual negligents (e.g., drunk drivers), thieves and con artists.
If a bankster's danger to society can be remedied by banning him from his chosen profession, and justice served with a fine, it does seem like we could spare the cage.
The thing is, the banker (or other white-collar criminal) is the only one who planned it. They, more than the thugs imho, should be locked away because they're predators not just opportunists.
And maybe we could spare the cage... But after we get around to the mistakenly (cough) convicted black people, and poor people, and those with mental illness, etc, then we can worry about the poor-banker in his comfortable minimum-security cell.
Well that's a fine point you make -- predators vs. opportunists. And I need to be reminded that wealthy white-collar criminals don't often experience the same kind prison as does the common man.
If a bankster's danger to society can be remedied by banning him from his chosen profession, and justice served with a fine, it does seem like we could spare the cage.