A big reason why I think the ending is totally absurd - -
The fact that Richard totally gives up on life immediately after he accidently brings himself back to 1980 really is ridiculous not only from a character development/story writing perspective, but the fact that Christopher Reeve faced much larger and tougher situations/obstacles in his own life and the man never gave up and kept on fighting to the end.
The fact that the Richard Collier character gives up so easily due to being in a situation that really is not one of true hardship really makes the story seem lazy and flimsy.