I can imagine some rides dont need 2 people to startup/run too. So its not like you need 50 people or something each day to get the work done. 

I would also imagine there is a lot of preventative maintenance that happens behind the scenes too. Not so much working when the rides are closed, but doing stuff in anticipation for when they are closed for maintenance aswell.

I think this video was better than the first, didn't think the Star Tour mention was that out of place. I felt it more emphasised the stairs are there for a reason and perfectly safe. 

Most of the coasters would need multiple maint guys to inspect in the mornings, but I'm sure the kiddie rides and possibly even DD could easily be done by one person.

If you wonder what they do during the day - stick around in the GL queue and you might spot a maint guy or two underneath one of the cars doing work.

Keep in mind in the off peak, on rides with multiple ride vehicles they will be doing annual maintenance on the cars not in use. IE Superman's 2nd train or one of Green Lanterns multiple trans.