Very interesting article. When you say "In Western culture," you are tacitly assuming that these are all similar. I've lived in the UK and USA (and have visited Japan several times) and there is a big difference between British "sorry," "excuse me," "pardon me," etc. and the American version (admittedly, the UK might have changed a bit since I left). But we Brits, make these kinds of comment much more frequently than Americans. I'd say that they are used much more like a casual sumimasen.