Another important factor with these "our bodies already have a natural mechanism..." arguments is that we don't eat the same foods that prehistoric people did w

Another important factor with these "our bodies already have a natural mechanism..." arguments is that we don't eat the same foods that prehistoric people did when they evolved, in addition to the fact that we now expect to live to 80-100 while still being highly mobile and having all our original teeth if possible. Prehistoric people did live to old age if they didn't get killed by disease or wild animals or accidents or murder, but they probably didn't look too good at that age and probably didn't have many teeth left either.