for us pros best buy seems like a rip off, money sucker etc etc with bad names. but they are not like newegg where they don't have to deal with customers. mostly everything with newegg is automated. but bestbuy has to deal with customers directly so that is 1000 times more employees to higher that means their net profit is less that is why they have to charge more. that is one example there are more... but i think you get the idea
I think the more plausible answer is that they do it because they can. Fry's also charges more than anyone else online but at least we're talking about being only 25% over newegg or simply not marking down old outdated products that have been hanging out on their shelves (you can't really complain about that). They're a steal compared to Worstbuy (I have my own issues with the big blue store). Bestbuy people go to Bestbuy first and foremost. They will pay more simply because they shop at Bestbuy, plain and simple.