Getting into the Senate is the politician equivalent of an academic getting tenure
I have no idea how true this is? It is just a random shower thought.
It may be more true where I am in Canada than in the US? Here, senators are essentially appointed for life. I understand US senators are elected but have longer terms and generally more stable careers than their counterparts? In either case, there seems to be a lot of prestige that comes with the position.
6 years per term, here, but no term limits. Combine that with name recognition, low-information voters, and "the devil you know", and they're basically / de-facto appointed for life, as you say. They can and have been voted out before, but it seems to be rare these days. Usually they retire (Manchin, supposedly), resign (Franken), or die of old age in office (Feinstein, Byrd).
In the UK the house of Lords is like that but in Australia the upper house has 6 year terms and have to go for reelection. Seats change all the time. Very few are safe seats.
I think the Canadian system is very much modelled after the UK?
That's interesting about Australia though. Btw I understand Australia has a ranked voting system in elections? Curious about how well that works. Our first-past-the-post is a nightmare with vote-splitting sending the "wrong" representative to the capital.