They were told that it failed as a TV show because with good comedy, you actually have to actively watch it to enjoy it.
Apparently too many people watch TV passively, or in the background - and thus all those carefully constructed gags the Zucker-Abrahms-Zucker team formed went unappreciated.
I had read that. From Wiki:
Police Squad
https://en.wikipedia.org/wiki/Police_Squad!
Cancellation
ABC announced the cancellation of Police Squad! after four of its six episodes had aired in March 1982. The final two episodes were aired that summer. In an interview for the DVD release of the series, Nielsen said ABC entertainment president Tony Thomopoulos asserted Police Squad! was canceled because viewers had to pay close attention to the show in order to get much of the humor: “the viewer had to watch it in order to appreciate it”.[25] Nielsen also thought the premise was more effective in the successful Naked Gun films because the much larger screen size in a cinema increases the efficacy of the visual gags. In its annual “Cheers and Jeers” issue, TV Guide magazine called the explanation for the cancellation “the most stupid reason a network ever gave for ending a series”.[26]