this is a false choice; no one would credibly make that sort of claim about audio-only courses in podcast form or video recordings without audio. you're focusing on the economics, and that's fine, but the court is focusing on whether it complies with the law.
Keep in mind that these are recordings of a professor talking - there is no script, no captions exist already.
The choice is paying for captioning, or not releasing at all.
If they are unwilling to pay, which should, in your opinion, they pick: Not release, or release without captions?