The big places with union labor I’ve been it’s often cheaper to run some overtime on an entry level position than it is to pay extra benefits to a new person. Plus if you’re running 24/5 then going to 24/6 occasionally is way cheaper than another or faster assembly line at millions each.
One place I was at was entirely salaried exempt employees, but they offered overtime at straight pay anyways. Result was that if people were motivated projects got done sooner, at no additional cost, and everyone was happy. Sort of like banking hours and then turning them in when times are lean.
On the customer side, some senior guy decided a project needed to move from 6 weeks out to next Tuesday due to an unexpected opportunity. Problem was that the parts weren’t even due from the machine shop for 2 weeks, they were booked, their guys need a break, and it was a holiday weekend. We agreed to +50% the price. The shop manager walked out on the floor and offered half of that to anyone who wanted to work 6 hours extra (basically double their usual rate). He had more volunteers than needed, we had our parts, and the shop had some extra profit.