People investing into teams would be hoping for the capital value of the teams to improve over time. NBL has been on an upward trajectory for the last few years, in terms of crowd numbers and now with a tv deal that, at face value, should provide a revenue stream. Teams would expect to get a dividend from that deal and so their capcital value woudl be expected to improve.
As an aside, a recent ABC article provided data on NBL revenue for 2020. It put NBL's revenue at $19,491,000; stated it was 10.3% down on the previous year's revenue; and stated that NBL made a 0.4% profit. i.e., about $760,000 profit.
Presumably this was just the NBL and didn't include revenue and expenditure for individual teams. Also, a table footonote states '2020 reporting period varies by sport.'. So it's not clear whether the data cover soem or all of the 2020-21 NBL season.
The article is online at https://www.abc.net.au/news/2021-09-23/coronavirus-local-and-professional-sports-data-impact-australia/100482976
There's a table about a quarter of the way down the page that presents the above data (together with other national leagues' data). To get the data, click on the 'Get the data' link below the table.