Considering the amount of hours, I think $40 is reasonable. I suspect it's much cheaper by the hour than buying a UFC fight or something from DirectTV. I mean, they cover literally everything from the full two days, even the concerts and tournaments, and you have the ability to watch panels that even attendees miss because they run concurrently with other panels. And I think you guys get the in-game rewards too?
If it was just a highlights reel or something, it would definitely be a rip-off. But it's a lot of content.
Opening ceremonies is free, btw. So if all you want is the big announcement and don't care about all the other hours of panels and tournaments and stuff, you don't have to pay anything. And of course you can get all the distilled information from the panels for free on websites like this one. So if the cost is not worth it or you don't care about all the other stuff it comes with, you won't really miss out on the important stuff.