A sub-lifetime appointment is also really bad for the Court system, too- the Court gets the final say in the law- and needs independence- and if we were to hold elections every few years for the Supreme Court, we would have an even more partisan government, as people would go campaigning for that office, with all its mud-slinging and hyper-partisanship that seems to be necessary to get elected in the United States' current political climate.
Sometimes, having an old guy say "whoa, slow down! That's a bad idea" is a good idea.
Having an elected judiciary is in itself a terrible idea, and not the only option against lifetime appointment. There's also term limits for appointments.
I agree with you, but also think SCOTUS and similar picks need to require a supermajority vote. That is, I don't have a problem with lifetime appointments to SCOTUS, but I do think if that's the case we need to base those appointments on some kind of trans-partisan consensus.
Sometimes, having an old guy say "whoa, slow down! That's a bad idea" is a good idea.