To make money.
... every other shop in the world pushing their old stuff for a huge discount.
Don't know about New Zealand, but in my part of the world you pretty often see shops offer products at a huge discount but with no guarantees or a no-return policy.
I used to walk by the local toy and game shops once a month and check out their 1-5 euro bins to pick up some older games. I usually know how to get them to work on my PC; great way to get a few older but still good games. Also great for LAN parties as not all my friends have a new PC.
No its not at all, there is a big difference between a retail store selling their own stock that they have already purchased and a manufacturer selling old unsupported stock.
A retailer wouldn't have that older stock to begin with, they would have parted with their 2010 stock in a sale when 2012 came out, it certainly wouldn't be on their shelves for 5 years. So you cant even use that as a comparison. Nor can you use " no guarantees or a no-return policy" as a comparison for no manufacturers support due to end-of-life product.