I am not saying that the market is or is not highly competitive. Personally with seeing such share markets of 80% and 90% and one even 98% I think they hardly differ much from monopolies especially since unlike internet businesses there is I would think a high barrier to entry and unlike PCs it is not a new market.
As for retail stores, at least in the UK, they hardly are competitive. We hear of price fixing all the time. They just engage in some game where they lower the prices by a penny and put them up by ten pence etc.
But in any event my point was not to conclude whether the market is or not competitive, but only to provide and alternative.