Just to put it in perspective: it costs $300–500 to produce a single atmospheric profile with current balloon infrastructure. The U.S. launches ~180 a day—that’s at least $54K daily. Not exactly “pennies.” :)
And the government already buys the helium, radiosondes, and ground systems from private vendors—so the money’s going to private industry anyway. It’s just inefficient.
With 50 of our systems doing 4 profiles a day (which is no where close to max scale), you get the same volume of data for way less. And on top of that, because we reach remote and oceanic areas that aren’t being measured today, the data is also more valuable!
Also, the data you’re referring to isn’t inherently public domain. It becomes public when the government buys it and redistributes it. That’s true whether they pay for the infrastructure themselves or buy the data directly from a company.