Unless they're corrupt and are only using their position to enrich themselves. What good is the institution if you can't make any money from it, especially when they see the other two branches doing the same?
I may be wrong about this, but I don't think "grubby wealth accumulator" fits the psychological profile. I think these are people more interested in power and prestige, and to an extent ideology and legacy. As they weaken the institution, they weaken their own standing.
Yes, that's a tough one to solve. Will need to amend Constitution to allow President to appoint and fire judges at any time. As to the 3/4 of states requirement, a creative solution will have to be found. For example, split Alabama into 20 small states.