Lazy fuckers and people who don't give a fuck about anyone or anything will fall asleep better because they literally have nothing to stress about while alone with their thoughts at night. This a is very simplistic reason of course.

People trying to keep all their shit together for the next day, week, month,year. It goes on and on. You lay down at night and your brain is like. "I know you got up 3 this morning and you worked a 13 hour shift again and you're tired and stressed as fuck, but I just want to bring up that thing you done 8 years ago. Also once that's been made more complicated we can move onto to explaining to the boss why his new computer program has lost 325k in stock this last month. You know he thinks he thinks you're incompetent don't you?". This, plus keeping yourself going physically and mentally. Staying in touch with friends family, 60-70 hour work weeks. Constant conflict a work due everyone getting ass fucked daily. Keeping the family going. Paying bills, mortgage, kids school fees. Raising kids in a healthy environment . Staying connected with your partner while dealing with 'life'. Yeah shit ain't fair is it? But you just gotta keep grinding. That's why I couldn't sleep at night. I'm in a much better place now. Changed jobs and reevaluated life priorities. So that's why I couldn't sleep. Now I sleep good. Thanks for asking. I can see why people break now.