If money is the objective, sure, some more people will pay... though probably not enough to offset the money teams were getting from the regional sports networks.
The Texas Rangers, as an example, had around 300K subscribers to its games on Victory+ at $100 per season... So $30 million minus operating costs, compared to the $95 million per season it made from DSG.
For long term brand health though? Free is the way to go. Think of all of the people in random areas of the country who are Cubs and Braves fans because they started watching those games on basic cable before they'd even been to Atlanta or Chicago (and before those teams were even any good).
There are three NBA teams in Texas, imagine if one of those teams had the balls to make every game available for free on YouTube. They would dwarf the other two teams in developing a long term following, which leads to more merch sales, higher ticket revenue, generations of fans, and more value when you sell the team. (And who knows what kind of YouTube ad revenue they could collect.)
I'm sure someone smarter than me has already run these numbers, and I realize players cost money, but I still don't understand limiting your audience when you are trying to build an institution like a pro sports franchise.