wareyaI think it's naive to assume that they must directly make money off of competitive players for it to be worth their effort. I mean, buying tickets to directly watch comp in Dota 2 was a brilliant idea, but it's all up to tourneys to work in that system if they put it there. They're not going to turn around and say "You can't watch tourney STVs yourself anymore, you have to buy a ticket"; they're gonna be like "You can ". And then you could have sponsors come in and be like, "Hey Valve take this money and make this tourney free to watch, let people know that it's on us!"
I do believe the hold up with this idea in TF2 is DotA 2 has dynamic STV allocation - STVs are created and allocated for tournaments (and public games even) as needed to match demand and the game will put you in one automatically. In Team Fortress 2 all STVs are basically servers owned by 3rd party GSPs and not managed by Valve, so this system would not really work nearly as well unless a tournament worked with Valve on it.
That and Team Fortress 2 does not have the broadcaster STV support that DotA 2's improved STV system has.
Basically what I'm saying is is someone should work with the i49 organizers to make this and an i49 in-game tournament ticket (that gives you a special hat that improves as you watch more i49 games) happen. Valve could kind of cheat the dynamic STV allocation by just providing their own STVs for just this event, but they'd have to do something about the shoutcasters :/.
Consider it a test run to see if there's demand for this kind of thing.
Honestly, if Highlander can attract tons of people mostly because of a small medal on your chest, a hat that gets sexier looking as you watch these tournament games should be big in TF2.
DotA is clearly the bigger and stronger game, but it's also more obvious ow the competitive scene benefits Valve there. Valve hasn't even tried to make the competitive scene benefit them in TF2 yet, and i49 would be a strong way to determine the validity of 6s as it is now.