I don't know what MS store you're looking at, but the one
I see when I go to the MS main page and follow the links from the front door to their store there is NO lists of Win 7 (any variety) for sale within the store. Now, some others have given page links that they appear to have from past hot links, they may or may not be valid sales via the MS store in THEIR country, but I can't get them to work right from here.
MS is SUPPOSED to be a professional IT company, and having faulty store info is NOT the actions of a professional company.
On top of that, MS has applied pressure to stop the supply of new systems with Win 7 to physical retail outlets in many countries. Yes, some of the vendor on-line stores will still sell some models with Win 7, but they won't sell them via the retail shops only to on-line customers. Many people do not like buying on-line for many reasons, a big one being the inability to properly check the product out before buying.