Two things to keep in mind -
Right now, the majority of students in college are women. How much longer will they be willing to subsidize sports for men through fees, donations, or attendance? Will Sugar Mommies give as much to football as Sugar Daddies do?
UVa has found that non-rev athletes give more money to the academic and athletic sides of the house than football or basketball players do on both an absolute and per-capita basis.
Again, if you look at it from a dollars and cents perspective, the majority of student-athletes in non-revenue sports have a bill to pay. They're not on full rides.
Taking a look at UVA, women's lacrosse has 32 student-athletes on its roster. They are permitted to give 12 full scholarships, per NCAA rules. There could be one or two that are on full athletic rides, but the vast majority have a bill. You can argue what the cost of that 12 scholarships is. I would argue room and board, as tuition doesn't cost the school anything to give (classrooms are going to be open). So that's $196,000 cost to the school.
For argument purposes, say 12 of those student-athletes are given full rides. This is assuming Virginia is fully funded in women's lacrosse (I'm sure they are - but some other sports may not be). 20 kids would be getting zero athletic scholarship. Meaning they will, at the end of the day, rely on institutional aid, federal grants, academic scholarships and out-of-pocket funds to pay for tuition, room and board.
UVA costs, according to its website, $33K (rounding) for in-state members and $67K for out-of-state College of Arts & Sciences students. Again, for simplicity, assume all are in CAS (other schools cost between $2K-6K more per year). There are 6 in-state kids on UVA's WLAX roster. The average need-based grant received by all UVA students is $23,439.
Do the math and that's a $9,561 net tuition revenue surplus for each in-state kid and a whopping $43,561 NTR for out-of-state kids. Which means, if all women's lacrosse players are getting, on average, what all other students get in financial aid, the program was a net surplus to the institution of $667,200 this year.
Per EADA's Equity in Athletics site, the total operating budget of the WLAX program was $276,136. Add in salaries which are probably in the $250K range for head coach, assistant coach, etc., and you're looking at roughly $625K expenses. That's a net surplus for running the program. Additionally, WLAX does sell tickets to their events, I'm sure has an alumni base that gives annually.
I would guess there is a very minimal cost associated with running the women's lacrosse program, but the added value for these student-athletes, coaches, and the student body is much greater.