Creator Killer: This was one of the shows that soured Fred Silverman's career at NBC.
Sadly, it seems to have been one also for Mei and Kei. Their time in America took them away from their Japanese fanbase long enough for their popularity to cool off, and so they came home to Japan after the failure of the show to find they had become yesterday's stars.
Executive Meddling: Big time. Basically, NBC just up and had Sid & Marty Krofft make this show for them (and lied to them in the process when Marty asked if the girls knew how to speak English). Secondly, Sid outlined the entire show, coming up with the idea that the entire show would play out of a Japanese music box... which NBC shot down in favor of a Donny and Marie clone (seriously, Marty Krofft actually said in an interview that NBC refused Sid's proposal/pitch, and told them, point-blank, "No, let's just do Donny and Marie"). Lastly, see Drop-In Character above. This eventually led to its premature, yet well-timed cancellation.
Genre-Killer: Though it definitely wasn't the last, PL&J's failure convinced programmers that the Variety Show genre was no longer viable.
Keep Circulating the Tapes: Averted for a short time. Rhino Entertainment briefly released the entire series onto DVD in 2001. Right now, the DVD set is out of print, but it can fetch a pretty penny on eBay—sets routinely sell for over $100, and have even reached as high as $175!
Old Shame: Even Marty Krofft is aware (and pretty much agrees) that this was one of the worst shows ever made in the history of television, and has acknowledged that Saturday Night Live has even done a spoof of it once.
Star-Derailing Role: Pink Lady's popularity in Japan had peaked in 1978, and by 1980 they had been rocked by a few scandals that had pushed their Japanese record sales into decline. So they shifted their focus to the United States, and ultimately gambled on PL&J reviving their careers. Except it didn't work out, and they disbanded a year later.