It's funny that Bzdelik inspired Pomeroy to come up with his formulas.
And as far as why schools don't do this themselves, realize these formulas for stats are pretty new, and only have started to gain acceptance the last few years by media and/or coaches. Plus, Pomeroy hasn't hid how he comes up with the numbers, besides his tweaks for efficiency. Anybody can use the formulas and a spreadsheet to compile the same or similar data.