There was one guy at work who told me he wanted to work until he dropped, he said he loved coming to work every day. Another guy hit mandatory retirement at 65 and DID keep coming into work. Both were at the highest level in R&D for nonmanagement, they both enjoyed a lot of "status". Needless to say, I had a different opinion personally.
I think my boss was shocked when I put in for retirement, he made some effort to talk me out of it, I made it clear I had made my decision. He also stayed a lot longer after I left I understand, for no perceptible financial reason.
There were some periods when I liked my job, I'd go in on Saturdays fairly often, those period were not prolonged and by the end I was completely burned out.
I think by 70 a person is pretty well time for the pasture. Go play baseball or something easy.