[gwern]

Try reading the article: the departments take a loss on each student. (But we'll make it up on volume?) It's the other departments like liberal arts which are cross-subsidizing them. (Which is cheaper to teach, a computer lab or a poetry class?)

[gertef]

Computer labs aren't so expensive. ~$3000 workstation, good for ~6 semesters, and multiple students per semester use one seat.

[gwern]

That's not even the beginning of the costs.

Again, the article directly addressed this issue. Read it.