As with any live sports, the goal is to sell ads. And you set ad rates as a function of viewer numbers. Producing a weekly Tebow special interest piece is considerably easier (and more profitable) than rotating through the other members of the Gators (Hernandez, Pouncey brothers, etc.).
Tebow is a very good athlete and he is extremely competitive. My guess is that he will not make the 53 man roster, but will sell a few jerseys and put about 1500-2000 more butts in preseason seats and the proceeds go directly to the Jags ownership. He'll provide the networks with a weekly pregame human interest story and will attract more TV eyeballs.
For reference, the offensive contributors on the 2008 UF National Championship team included the following NFL-bound players:
WR Percy Harvin, Riley Cooper, Louis Murphy
TE Aaron Hernandez
OL Phil Trautwein, Maurkice Pouncey, Mike Pouncey, Mo Hurt, Marcus Gilbert
RB Jeff Demps, Chris Rainey
That's quite a talented set of offensive players. Tebow had a lot of help.
For reference, the defense included future NFLers Joe Haden, Janoris Jenkins, Brandon Spikes, Major Wright, Carlos Dunlap, Ahmad Black, and Jermaine Cunningham.
The team was loaded.