I'm retired now but I use to work crazy hours and always got my workouts in. For a year I woke up at 3:30AM and drove 105 miles to work. Another point in my career I worked 4 days were I got up at 4:30AM drove 60 miles. When those 4 days were over I would have to work 4 days going to work at night getting home at 7AM for 8 straight working days then I got two days off. It helped that my job let me get my cardio in. They also had weight gyms but I rarely had the time to get a weight workout in. Cardio was quick. A 20-30 minute run and a quick shower always worked.
I found when I worked nights it worked best to work out before I went in so I could sleep when I got home. Working days I had to hit the gym immediately after getting home. If I waited for a couple of hours I just got too tired.
The first Mr. Olympia use to work 8 hours during the day. He would get off and get a 2 hour workout in then go to night school. He said in effect the strict structure of the day gave him the best workouts. Sergio Oliva before he became a cop during his Olympia reign worked manual labor for long hours. He ate like crap but always trained hard.
Sometimes you think if you didn't have a job it would be an ideal situation for working out but for many it turns into really bad habits of laziness. I would guess about 10 bodybuilders make a good temporary living at bodybuilding. The rest live like border line bums trying to get by. Putting the syringe life style ahead of a career will end badly.