Who is Dan Gunn, and why does he say suicide has become common?

Dan Gunn is a physician and Randy's best friend. Suicide became common because people were unable to cope.

They created and lived in an environment of paper profits, and when paper returned to paper they had to kill themselves, not realizing that their environment was unnatural and artificial. But it wasn't the adults that got me down, Randy, it was the babies. Give me another drink, a small one."