In what sense? Bed bugs don't care whether you're tidy or not, they drink your blood and hide during the day. You can have an absolutely spotless home and flawless personal hygiene and still have bedbugs living in your floorboards.
In the sense that washing your clothes and bedding at high temperature plus washing all the spots where the bed bugs could hide should keep them at distance.
The issue is that “all the spots where they could hide” is absolutely any kind of crack or tiny hole. Floorboards were mentioned, and you cannot really take that away to clean it each week. Same thing for wooden beds: those have lots of spaces where a bug can go but not much else, short of dismantling the whole thing. They can also be in sofas, bedside tables, cabinets, chairs… And these places are not dirty, they are just available space. Fumigation is a way of getting rid of them because otherwise it is impossible to access the places where they hide during the day.
No, it is not. They eat you, not your waste or byproducts. It is a human problem. Or do you think also for example that mosquitoes are a personal hygiene problem?
Living in a home without clutter helps you deal with them because there are fewer places for them to hide. But this will not prevent spread or occupation by them.
Steaming is an effective treatment but only reasonable if there is no clutter and minimal furniture.