and what killed the TBird - was predatory pricing by the dealer network. all the initial interest in the cars, was bled away by dealers asking $5-10K over sticker for them. that finished it off, once you kill off that initial interest in a "niche" car with that, its dead.
Bill Ford was quoted saying the car was 1,000 pounds overweight. Sales of T-bird actually took away from sales of other Ford products.