I can't speak for other people.
I can tell you that when I started out, I struggled in homes with lots of clutter when I knew the client had a fixed budget. I knew I want being paid for the time it would take to move everything and put it back and I woukd get into a situation where they've paid me for say, 3 hrs, but 2hrs in, I've really done everything I can feasibly do in that time.
Now I am better at being honest about that and saying that the areas which need to be cleaned to make the home look and feel cleaner are inaccessible. If the client is understanding about this, I'll make suggestions about how we can work within their budget to get to a place where there is a point to me being there.
Some people arent amenable to those changes and so I part ways.
It's simple, if you want to keep everything trinket and photo and whatever from your whole adult life, then you will have loads of dust on your shelves unless you keep on top of it weekly.
If you add kids to that, it's going to be a nightmare.