Why did Dreyfuss look the same in the 80's as he did in earlier times?

This is the only problem I had with the movie. The fact that Dreyfuss looked the same in the 80's as he did in the late 60's, 70's...like they only had one make-up process that could be applied.

The same goes with William H. Macy. He looked identical as well, with a 60's crew cut in the 80's.

It's almost as if the director/producer didn't originally intended for the movie to advance into the 80's.