When they were that kind of age it could take me an hour and a half too, more sometimes, but that was mainly because it was entertainment for them that I liked doing. I liked playing with them (or watching them play) in the bath and I liked reading them stories. If bedtime had been 5 minutes then I would have had to find something else to do for the other hour and 25 minutes and I had been doing that all day.
As they got older they were better able to entertain themselves and bedtime got shorter. About the age of 7, when they stopped wanting us to read to them, it took us about 5 minutes to put them to bed. We would say "Okay, bedtime." and they would go to their rooms, put on their pjs, clean their teeth and get into bed with a book. We would pop in about 10 minutes later to make sure everything was okay, and again just before we went to bed to make sure they were asleep.
But then they their dad decided it was a great time to talk with them so the first pop in now takes him up to an hour! It's not really putting them to bed though (just as my marathon bath and story sessions weren't), it's bonding time and they all seem to love it. I still do the 1 minute check in when we go to bed. They aren't always asleep then any more, but they stay quiet and they wake up after us so it's all good.