I'm technically 9-5, though I can choose 7 to 3 or 8 to 4 if I want. I usually work 7-4 and take extra breaks throughout the day (or a really long lunch). Granted, I work for a non-profit which has a LOT less bullshit to deal with. I also have the option to work 7-5 or 8-6 if I want to only work 4 days a week. Flex time is an amazing fringe benefit.
Outside of salaried jobs, I haven't seen anywhere mandate 7-5 schedules for hourly employees (unless it's a 4 day work week). Companies do not like paying overtime, so most I've dealt with will send you home the moment you hit 40 hours.
Flex time was one of the best parts of working in government. Being able to craft basically any schedule so long as it was 40 hours and not more than 10/day was really useful.