I don't disagree with your comments about Best Buy's own role in its downfall. However, at the bottom of the slippery slope of failing retailers is Walmart, who survives by undercutting all its competition via massive scale. Walmart is certainly not known for its knowledgeable sales people and great customer service. The only other tech option locally (Minneapolis, MN area) is Microcenter, but there's only one on my side of town and it's a much farther drive than BB.
Geeks like us will always buy our niche components (e.g. graphics cards, HDDs) online. But I do make the occasional visit to Best Buy for accessories such as keyboards, mice, and headphones that I want to touch before buying. I did the same at CompUSA, CircuitCity, and countless other deceased stores. It's a shame they have to charge tax when the base price is the same as Amazon's. Retailers have a legitimate complaint that buyers do their hands-on research in-store then order online to get a better price. If stores didn't charge tax this wouldn't happen nearly as often.