Why do politicians who are past their sell-by dates run for President?

[Phony Moderate]

Attention-whoring, money, for the sport of it etc are the answers I suppose, but, just for amusement, let's take a look. It seems to get worse over time, also.

1960: Adlai Stevenson (well, maybe he would not have been...if he hadn't already lost two general elections)
1964: Harold Stassen (everyone's favorite. I won't bother listing him again for obvious reasons)
1968: None, really. Nixon may have seemed like one at the time though.
1972: Hubert Humphrey, seriously. He was done after 1968.
1976: Ummm...George Wallace's brand had become stale I guess by this point, plus he'd been shot in '72.
1980: As in 1968, two pretty strong fields of peak politicians...I suppose Connally though comes the closest.
1984: George McGovern! I love the guy but wtf. Also, Mondale was probably politically dead for being VP under Carter.
1988: The Dem field was as weak as goodness knows...but all were at or near their peak. On the Republican side, the clear winner is Alexander Haig.
1992: Eugene McCarthy!
1996: Bob Dole. '88 was his time and he blew it.
2000: Dan Quayle....he likely just wanted the experience of a run after having been forced to decline in '96 through illness
2004: Dick Gephardt
2008: John Edwards, Mike Gravel, Joe Biden (to an extent), Fred Thompson, Jim Gilmore, Tommy Thompson...yeah, this is when the stale candidates game took off
2012: Buddy Roemer, Newt Gingrich, Rick Santorum, Gary Johnson
2016: Now this is just silly...potentials include Lincoln Chafee, Jim Webb, Joe Biden, Al Gore, John Kerry, Howard Dean, George Pataki, Mike Huckabee, Bob Ehrlich, Jim Gilmore, Carly Fiorina (not that she was ever in date), Rick Santorum, John Bolton...a more controversial case can be made for a few others too...