My local brick and mortar store are automatically at a 7% price disadvantage because they have to include sales tax to items purchased where online retails don't.
No, your local brick and mortar store is at a 15-30% disadvantage simply because they charge a lot more for most things.
I just bought a gaming headset at a local B&M because I wasn't sure if it would work for me (comfort, quality, etc.) and wanted an easy return if I had to. For that, I paid 44% more than if I had purchase the item from Amazon. This is not an unusual situation, at least as far as tech is concerned, with Amazon, NewEgg, SuperBiiz, etc., all fighting for my online purchases.
Also, Amazon charges tax in my state, so that part doesn't even enter into the decision to buy online.