Here is a Forbes article from 2014. Maybe it can explain better than I can why booster money is a necessity. Click on the links within the paragraph I posted.
The Most Valuable Conferences In College Sports 2014
"The nation's collegiate athletic programs receive healthy cuts of conference distributions - last year most Big 12 schools
got $22 million (new members TCU and WVU only received half-shares of $11 million) - but the schools have their own expenses to account for. And those expenses
can be incredibly high. According to the numbers in the Department of Education's
financial database, half of the members of the ten most valuable conferences lost money last year, and only one-third of them netted a profit of $1 million or more.
There may be a lot of money getting passed around but, for most schools, at the end of the day there isn't always a whole lot left over. "