It didn't die, IMO.
It solidified it's base. Fans are MORE dedicated today, but they're less of them.
Today, 20k people checked getbig to see what's new in the sport.
many more hit other forums all to follow bodybuilding.
Granted, more people saw it when it was on ESPN every thursday afternoon. But as far as dedication and FOLLOWING the sport... I"m guessing the numbers are fewer but far less casual. Most of us here can tell you an interesting fact about the top 10 finishers at the Olympia. I betch 90% of them will still follow the Olympia in 10 years. On the other hand, the fairweather ESPNers who just watch whatever is on, they haven't followed BBing in years.
So I think the sport isn't dying - instead of having a bigger, more casual fan base, it now has a smaller, yet more dedicated base.