If Feinstein can still be around, why not Warren who actually contributes.
Eh, not exactly a fair equivalence: Warren suffers from no evident health issues, & serving a 3rd term would - in the event that she doesn't then seek a 4th term - leave office at only 81, compared to Feinstein, who's actually exhibiting signs of dementia, sought a 6th term at 85, & may very well seek a 7th at 91, if the existence of her 2024 campaign account is to be believed.
While there is an argument to be made here, I would push back against the idea that there is some kind of maximum age past which one cannot be an good and/or effective Senator. Just look at Robert Byrd - he served the state from when he was 41 all the way until his death at age 91.
There is some value for seniority also - especially so for a state like California. If you have just as many members as Wyoming despite having a much, much bigger population, then it is important to have long-serving people in high places in the chamber.
One doesn't have to vote Feinstein, and I actually favored Kevin de Leon back in 2018, but it's important to note some of the valuable things for the state of CA that it has attained on basis of having Boxer (since retired) and Feinstein. And that a rational voter can value that long-term incumbency.
