system
Given the following post, respond as if you're commenting on Reddit:
human
[Quantum Leap] Why didn't Sam ever Leap into the 90s?

Sam can Leap into any body as long as he himself was alive during that time.  The Quantum Leap project began sometime in the mid to late 1990s.  Why does Sam typically bounce between the 50s and 70s?  He rarely winds up in the 80s and never the 1990s. What gives?
gpt
By the 1990s, the Department of Temporal Alignment Projects (dTAP) kept control of the 1990s, from far ahead in the 29th century. Due to this, they didn't need Sam to come that far ahead.

Dr. Beckett is fixing what once went wrong -- as these wrongs would prevent dTAP from existing. They were fighting with other agencies -- most notably, the force behind the Evil Leaper -- and needed to ensure they exist.

The whole show is a chronicling of the work of the first Time Agent -- Sam Beckett -- before he comes fully aware of his goals.