I wasn't commenting on the suitability of "This American Life" for TV, although I quite agree with you on that point (I suspect the show would have lasted longer on HBO, say, which tends to give its failing shows more than two seasons unless it features racehorses that keep dropping dead). I merely meant that the creators of a series would still prefer to get on television in whatever way if that's an option for them. "This American Life" would never have made it to the networks but I expect those behind the series would have been thrilled if it could.
Just curious - why do you think they'd prefer to be on TV? Bigger audience? Superior medium? More dollars?
I don't know how many people listen to the actual radio broadcast of TAL, but more than 500,000 people download the podcast each week. The top cable TV show last night
(4/26/12) was "South Park" with a total live + SD (same day DVR) audience of 2.3 million. The total audience for an episode of the radio version TAL can't be too far behind that. (The top broadcast TV show last night
was "American Idol" watched by a grand total of 16.8 million live and SD.)