It has survived everything from a serious accident at Le Mans in 1955 that came close to killing the sport over safety issues; to mid 70's fuel crisis and tightening emissions/noise pollution regulations.
Now I believe the greatest threat is coming from several directions -
Gen Y is generally uninterested in racing and cars in general. Traditional racing such as stock cars and Indy car has sunk to all time lows. Some blame the terrible television coverage.
On this week's Mid-Week Motorsports, a good chunk of the show was devoted to talking about the mishmash that is internet streaming of racing including; horrible highlights packages, geo-blocking to protect local viewing contracts and other shenanigans.
As was touched on, old media has no clue about new media. Otherwise it would be more widely used. But honestly I think they are protecting senior leadership that operates the cameras and makes the decisions in the production truck.
Moving to robotic cameras and using three man crews (the call, color and pit-lane) reduces production cost significantly. For example this weekend's Tudor PC, IMSA Lite race at Kansas won't be seen anywhere, unless you go to the track. It could easily be done with two/three man crew and four cameras because its a roval.
All that said, giving access and gauging interest are basic marketing failures by all the major racing series.
There is no explanation for camera and audio problems that plague SCCA World Challenge. What the hell was the TC/TC-B race in New Jersey? One camera on top of the timing tower, really? I mean REALLY???? Since the start of this season they have eliminated post race interviews, forcing fans to watch the highlighted coverage on NBC-SN.
This is 2014 there should be no excuse for this. What's hard to understand is why the fanbase is so quite about it?
In Part 2 like my video -
I'll break down what all these series can do. One of them is to secure your base before pursuing the mythical casual fan. They could start by NOT REPEATING THE RULES at every single race!