This also happens in the UK, except that many of the stores themselves are owned by the same conglomerate.

Also easy to offer a lowest price guarantee when you know that customers are likely to only shop around at the high street 'competitors' which you also own. Will they bother to shop around? Doesn't really matter - heads you win, tails you win.

Although this probably works less well with much of the demographic of people who buy computers in the online shopping age.