What a totally BONKERS idea is that. !!
it's APPS and the whole concept of a "Store" that's passé not the add-ins.
Obviously copied from Apple who has now peaked and can only go downhill from here on in. (Ipods -- huge and successful revenue source at one time but who needs them anymore -- more and more phones have decent music players incorporated into them and with removable storage cards of up to 32 GB in them the Ipod is now a redundant piece of kit, Ipads-- the whole tablet segment is fragmenting and the Iphone looks positively dated by comparison with the newer offerings from HTC and Samsung -- and I haven't seen it yet but the new Nokia Windows phone is alleged to be pretty good too).
Apple only have their macbooks which sell basically on "Looks" rather than value for money and that is purely a niche (and not growing) market and of course ITunes which is either loved or more usually Loathed with a passion.
Even here the Ultrabook (expensive , sleek and incredibly powerful laptops - often with i7 processors in them with SSD's USB3 etc) is eating into this market as some of these look every bit as good as a MacBook and are incredibly useful and portable -- please DO NOT GOOGLE for these -- your bank balance will shrink immediately by a significant margin --these very thin and light extremely portable models are one of the few growing areas in laptops and with good reason !!!!!.
If I were a developer selling my stuff online directly where I get 100% of the sale why should I let Ms take 20% for the "dubious privilege" of allowing - and later - forcing the program to be sold in the "app store". Even the overhead of maintaining my own web site wouldn't cost anything like that for a small operation.
I've removed the store anyway off my start screen
When will the stupid scrobbits over at Redmond realize that a laptop / desktop computer is NOT a tablet or a smartphone where this type of operation makes more sense.
In any case how is Ms going to stop traditional Windows software from being installed by "the usual Methods" - and in any case in the EU restricting development like this might be against monopoply or anti competitive legislation too.
Finally -- imagine you have to re-do your whole A/R and A/P finance depts. (accounts receivable and payable). Now I'm no finance guy but it's going to be a NIGHTMARE dealing with 100,000's of individuals possibly selling as few as 10 - 100 apps per month at say 35 cents a pop plus maintaining all the different taxes applicable in various jurisdictions around the world both for the purchaser and the developer of the app -- love to see the extra cost of maintaining all these on Ms's billing systems -- and if this stuff is "off shored" I pity the developers from ever seeing their money in a reasonable time frame - even if it is only 35 USD they are expecting. !!!!!
Some of the top boys (and girls) at Ms have obviously spent too much time in one of those Amsterdam Coffee shops smoking that "funny smelling tobacco" (or locally known as "Waccy Baccy"). !!!!