It's hard for me to fathom that franchises will continue to rise in value as they have done in the last 20 years, but it's also an area of the economy that is extremely hard to predict. As the richest people continue to get richer, there will be people who will spend billions on a team, with very little (relative) return. At the same time, I think there is going to be a point where people (overall) decide to spend less on professional sports as entertainment.
In general, huge investments (e.g. 1.3 billion dollars) would be much less likely to increase exponentially than smaller investments. There's only so much room to grow.
The 100x increase you mentioned would bring the Buffalo Bills worth to 130 Billion dollars. That's Dr. Evil money.