ADA imposes much more expensive mandates to much smaller businesses, and I'm under the impression that most people consider that to be acceptable.
That's really not a lot. Probably blame a dumb and inflexible budgetary process.
Have you ever tried transcribing a video in a level of detail such that someone who can't see the video has a full understanding of what's going on? Give it a shot and report back to us.
Source: I've actually transcribed instructional videos for disabled students.
Update: Google suggests budgeting 4-9 hours of transcription time per hour, which is closer to my experience.
You might get by with 4 hours if it was just someone talking (with no slides, etc.). If the person performing an activity (say, a lab course) 9 is going to be a lot nearer the mark.
Remember, this has to be done so that both deaf and blind students can use the material.
"Automatically generated captions were inaccurate and incomplete, making the content inaccessible to individuals with hearing disabilities."
So it seems like they need to be quite accurate.