It’s pure laziness on the part of the voters. It’s easier to vote for incumbents than to do the research and see what your Rep or Senator actual did or didn’t do when in office. Did your Rep or Senator stand up and vote no for bigger government or spending out of control? What did they do for you and your state? A lot of voters just vote for the name they recognize.
I refuse to vote for an incumbent. Even if they were ok they are still part of the problem
Bingo...we have a winner...”A lot of voters just vote for the name they recognize.”
And therein lies the problem. As you msg states people don’t take the time to see what their Congress critter has actually done or not done. I get it...people have lives and politics are really not a part of it.
The rise of populism, e.g. the MAGA movement, was a result of people who do actually vote and pay attention. Their Congress critters were NOT paying attention to what the people wanted done and so we got Trump. He rode that populist wave into office. It could have, in my opinion, been anybody, not just Trump, who got elected if they articulated the populist sentiment.