It happens all the time. There was a time when the NBA was the so-called
"fastest growing sport in America" and that just happened to coincide with
the careers of Michael, Magic, Larry, and Charles. When those guys left the
NBA to be replaced by heavily tattooed and cornrowed thugs like Iverson the
ratings promptly took a nosedive.

Currently the NASCAR is experiencing the same thing. Dale, Rusty, and Bill
left the game only to be replaced by drivers who seem much like clones. And
they are dull clones at that.

All of the American sports experience ups and downs and it almost has to be
that way. Otherwise some of them would have 100% of the people surveyed
calling themselves fans and others fading away completely.

What happened to open wheel racing in America was essentially that all of
the household names retired within a relatively short period and were
replaced by drivers who the public did not embrace. There is a huge
difference between misfeasance and being part of a changing world.