They get paid 274k...DC is expensive, but anyone that can't live very comfortably on that is awful with money. Being awful with money will lose you a TS clearance because it makes you susceptible to bribery by spies. I would think it would also be a disqualifier for a SCOTUS judge for the same reason.
I think maintaining a TS clearance should be a requirement for all positions above a certain level in the federal government. Not because they need access to TS information, but to ensure they are at a lower risk of bribery, adversarial interests, and criminal activity. Getting a TS clearance isn't terribly hard. Just generally have your act together. As long as you aren't a train wreck, a drug addict, a criminal, an untrustworthy asshat, or have connections to adversaries, you will pass adjudication. TLDR: A TS clearance would ensure high level government employees are minimumly functional humans.
Dozens of other nations: "What they said!"