"Great baseball towns fill the seats even when the team is out of contention."
That is not true.
New York Yankee attendance from 1989 to 1996: 26,963, 24,771, 23,009, 21,589, 29,839, 29,656, 23,521, 27,789 (From
http://tinyurl.com/67yr9tf) Not coincidentaly, these were the last years the Yankees were not good. They have contended every year since 1995. Won the World Series in 1996 and haven't looked back.
Boston Red Sox attendance from 1981 to 1985: 19,637, 24,076, 22,004, 20,514, 21,922 (From
http://tinyurl.com/pz7bv)
In 2003, the Detroit Tigers, one of the most storied cities in baseball drew 17,103 per game. In their history the Blue Jays have only drawn worse than that once (in 1981).
So, by your definition New York, Boston and Detroit are all bad baseball towns.
When a team has a prolonged period without a playoff race its attendance struggles. Even with the legendary teams sometimes.
The Blue Jays, without a race since 93, have averaged mostly in the low 20k's this decade, peaking at 29K in 2008. That is nothing to be proud of, but given the cirucumstances, neither it is unexpected.
I suggest you look up the history of Toronto baseball on wikipedia - the Toronto Maple Leafs baseball team in particular. Baseball has been part of the city for a VERY long time (site of Babe Ruth's first professional homerun). Nobody is saying it's close to hockey, but the sport is part of the fabric of the city (despite the recent doldrums brought on by being a perennial also ran).