There are still some countries that do not have paid apps available for them and google is not pushing this.For example; i am living Turkey and i had spent more than 150$ on apps for my ipod touch in months but now i have bought a galaxy s 2 and i don't have google paid apps available to buy. I have posted on android market boards, also contacted phone manufacturers and carriers about this but all of them point their fingers at google. So since google is not willing to listen willing buyers i think it is time for developpers to talk with google and tell them you want more customer base and countries like Turkey where there is a huge potential (75 million population with huge proliretaion of and android devices through carriers) are great for this puposes.
As a customer i have to tell you that i am sick of google making me have to be pirating paid apps and downloading untrusted apk's from torrent sites, if you take this cause seriously i am sure in long term you will be profiting from this.

Thats a fair point. It seems really strange to me that Google hasnt done more about this, as the only thing it would do is put cash in their pockets, and in the pockets of developers. I also wish they would do more to improve market in general, such as add bank transfer and paypal payment options. After all, the more payment methods you have, the more people will buy.

I started to believe there can be 3 reasons. 2 of them local, 1 is google global policy.
First, their Turkish office is useless, they do nothing but drink coffee on a very expensive building floor. I never seen a Google ad in Turkey, no public relations at all.
Second, their Turkish office seriously made the government and politicians nuts by not being serious, it is a global thing since beginning of history. Never make tax guys mad. They do very strange things like routing receipts from Ireland and government says they won't allow such behavior. They are clear, to do business here, you have to have an official office, accountants and someone to take accountable. Apple has all, Nokia also has everything but google wants to ignore.
It could be the tax guys saying "don't even try to sell software this way"
Third reason? Google sells ads, they are a gigantic advertising company. So why not make a lot of money from a "free" app with their ads instead of getting 1 time cut from poor developers $3?
There is a serious conflict of interest there.
Developers are also being lazy and ignorant for putting only google app store option to their apps. Google licensing sdk is not an excuse, I have purchased apps using that scheme but paid via paypal. So there must be a way.

I could be wrong, but I think its very complex why it hasnt happened yet. Android users have been begging for Paypal support for SO long, and Google KNOWS how much more revenue it would drive to have additional payment options, yet it still hasn't happened. Have you ever thought about emailing Google directly and asking them about it?

I tried, all I got was a template. Funny is, Apple Turkey and Nokia was the last ones I expected an online store, especially Apple.
I am not in love with google, it is the developers, shareware developers and their apps I care about. I rather pay rather than being profiled.
What is the reason for a developer not selling their software in this site's app store but on google app store? I am not very fond of them but they aren't Apple, I don't think they care and do evil things to developers.

It depends. To me, it makes sense to have your app on as many platforms as possible, but for many its easier just to deal with Google directly, as it might make customer support and payment problems easier to deal with when just using one market.