Ex HMV employee wading in here...
I worked there between 1997 and 2001. Back in those days, albums were the big sellers. The company as a whole didn't care too much about singles. Videos (remember them?) came just behind albums, and the idea of selling mobiles or anything 'techy' was just stupid. It was an industry of music shops with the business model of employing staff who knew their stuff. The company admitted it was more expensive than other retailers but it prided itself on having staff who could answer questions rather than just standing at the till shouting who's next?
About a year after I left, a friend who still worked there told me it was changing. Management wanted staff to focus more on pushing various new plans (loyalty cards etc) rather than using their knowledge to order stuff that would sell. Now thanks to people being able to download singles rather than having to buy an album to get what they want, as well as reality TV singing contests, singles are where it's at and people generally don't care about albums. And on a sidenote, the shop I worked in is closing down in a couple of weeks while the larger HMV inside the shopping centre (previously a Virgin until it closed down and HMV took it over) is full of X Factor albums and staff shouting who's next.
All this is a long way of saying HMV has let itself go down the toilet and it wouldn't surprise me if they take Waterstones with them.
The one in Manchester, round the corner from me, that was a Virgin and now a HMV...
