In my view some of those USTA estimates are very inflated. They estimate the value of a full-ride scholarship to be approximately $90,000 a year. I would use just what a walk-on would pay out of pocket like the cost of tuition which is about $50,000 per year. The other 40K the athletic department pays for such as equipment, travel, coaching, tutoring etc.
The USTA estimates a player must earn about $143,00 to break even yearly. Again this seems inflated. This is probably for a player who played the maximum amount of tournaments allowed and had a full time traveling coach. For most players outside the top 100 who travels alone the cost is probably half of that or 50-70K which is what I would use. I've heard for men you need to be ranked in the top 300 to break even. For women it's probably ranked around 250 to break even yearly.
The proper decision tree is to compare the value of turning pro to the value of a year in college. Thus, you should count equipment, travel, and coaching as you would have to pay for this yourself on the pro tour. The $90,000 figure seems reasonable in that light. You can also count the tuition, even though you wouldn't be paying for it on the pro tour, because it is an investment in a career post tennis, which you would have to pay for yourself after the pro tour, unless you are Kim Clijsters, and even then, most of them end up going to some sort of school, it seems.
I agree that $143,000 seems high. Let's use $70,000.
To break even, players would have to earn $150,000 per year on the pro circuit (assuming a 40% tax bracket, to cover the $90,000 tax free benefit of an education). Essentially, a player must notch four years in the top 100 just to break even. How many players do that? I'll tell you one thing: virtually no one who even has to consider college as an option will spend four years in the top 100.
I wish college were the standard route for top junior tennis players.