In late March, Quinnipiac University released the results of a survey of New York City residents on their baseball tastes. According to the survey, 46% of New Yorkers are either "very" or "somewhat" interested in Major League Baseball. Of those, 61% say the Yankees are their favorite team. 27% said they root for the Mets.
Accepting WorldPopulationStatistics's numbers, the population of New York City is 8.33 million. That means there are 3.83 million baseball fans in New York City, 2.33 million who root for the Yankees and 1,034,100 who root for the Mets. Granted, this only New York City, not the greater New York metropolitan area, which totals over 15 million people.
Extrapolating these numbers to the populations of Tampa and St. Petersburg (333,073 and 249,704 respectively), we get 268,077 baseball fans in our Bay Area cities [(333,073 + 249,704) x 46%]. Of course, the Rays don't have to compete with another Major League team in the area, so we don't further divide.
This means, if baseball fandom is equal in the Tampa Bay area as it is in New York City, there are almost four times more Mets fans in New York City than there are Rays fans in Tampa and St. Pete.
If we include statistics from Quinnipac University's most recent Florida sports fan polling from March 2012, 46% of Floridians are baseball fans - again, either "very" or "somewhat". Of an unknown number polled in the Tampa Bay area, 54% of baseball fans are Rays fans. Using the wider Tampa Bay metro population of 2.8 million, that means 695,520 Tampa Bay area residents were Rays fans as of March 2012 (2.8 million x 46% = 1,288,000 total baseball fans x 54% = 695,520)
Combining the 2012 and 2014 data, we find there are 32.74% less Rays fans in the total Tampa Bay area than there are Mets fans in just New York City.
In 2013, the Mets drew 2,135,657 fans to Citi Field. That would be 2.06 times their New York City fan base.
In 2013, the Yankees drew 3,279,589 fans, or 1.4 times their New York City fan base.
Last year, the Rays drew 1,510,300 fans. That would be 2.17 times their total fan base.
If Tampa Bay had the population of New York City (8.33 million) and the same percentage of baseball fanbase (46% or 3.83 million), the Rays would draw 8.31 million fans (3,830,000 x 2.17 = 8,310,000).
And no one would complain would about attendance ever again.