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.
The US intelligence apparatus doesn’t do this. The OPM does.
As per your second paragraph and many other comments. I agree. It is hard to avoid it being politicized at any step of the process. Everything interview would have to be recorded. Copies of all reviewed records would need to be kept. Adjudicators would need heavily redacted transcripts of the records and interviews.