Honestly, I don't know if things are just different in other countries (than the US) but the idea of a retailer providing technical support in most cases is absurd. Considering a retail chain can sell thousands of products, there's simply no way that can provide support for all those products. The only kind of support you should expect is a refund (where applicable) or exchanges. Anything else should go to the company that makes the product.
Even Microsoft supports their own products. (Before Microsoft pulled their contract, I used to work with a company that was contracted with Microsoft for their products.) If they expected retailers to support their products, they wouldn't bother providing support at all.
As far as markup, you're forgetting that the distributers get their chunk of the pie too.. The retailers aren't the only ones that add to the cost of the product on the consumer end.
