Power. And need to feel useful.

The US legislatures give a lot of power based on seniority. There's a lot of incentive for a party to keep members in office as long as possible.

When these people are strong and healthy they need to foster the next generations so that the party has a good idea who their successor should be so that there party doesn't fall into shambles and infighting every time one of them dies or retires.

The problem is that they don't do that. It is in their interest that there are no viable alternatives to them because good alternatives to them threaten their power. Until they are suddenly 80 that is and nobody knows how to replace them so they have to sit on their thrones and hold on for as long as possible.

People who made it that far up are usually very driven, their job is their whole identity.

It's probably hard to walk away from something they dedicated so much of their life to. More so if it involved sacrificing time for relationships, family, friends, etc.

Someone else recently explained it best: It's elderly abuse.

The entourage encircling these elderly congressional leaders are profiting greatly. As soon as these senators retire, these leeches lose nearly everything.

It's a Weekend At Bernie's movie plot, but with extra steps.

Seniority plays a major role in committee appointments. Sure, you could replace the senile 95 year old who doesn't know the cold war is over with a younger candidate, but that senile 95 year old has been in Congress for longer than the other guy has been alive, and he's on some important committees because of it that the younger candidate wouldn't be able to be in

True, but this is only part of the solution. Term limits can cause the real power locus to move to those unlimited proximate positions. A holistic solution involving congressional term limits, limits on staff and lobbyists, etc that all work in concert to prevent hoarding of power is what's needed.

This would solve the issue without being ableist

age limits; term limits have some actual negatives like getting rid of good representatives and increasing corruption.

At least his eyes point in the same direction