From [topcoder.com/stat?c=country_avg_rating] the organization responsible for the competitions and the stats.
Computer programmers can. Attention to detail is critical in this field. It's their job to be precise. Did you already forget what is being discussed here?
can someone tell me why recently (since WW2) nothing highly advanced has come out of Poland?
It did. You simply don't know because you are a young kid interested in games, which btw. are coded by quite a few Polish programmers, who acquired their skills in Poland. You may have heard about siliconknights.com/main.html Silicon Knights Inc and their latest game "Too Human". I happen to know the owners of the company and at least a dozen Polish programmers working for them.
The fact that you don't know this or that, or that you haven't heard about one thing or another only says something about you.
Now, on a more serious note, Poland was penalized by the USSR for its slow pace of communist developments. The punishment was designation of Poland as an agricultural country withing Comecon. Bulgaria was name an IT centered country within the Soviet block. You are certainly familiar with some of Bulgarian programmers' efforts, at least indirectly. Up till about late 1980's about 50% of comuter viruses came from Bulgaris.
I wonder how many of the inventions below have you heard, and how many of them do you even understand.
Henryk Magnuski - inventor of Walkie Talkie, which, eventually, has evolved into cellphone.
Mieczysław Gregory Bekker - one of the key designers of Lunar roving vehicle.
Stefan Kudelski- inventor of Nagra audio recorders
Tadeusz Sendzimir - invented revolutionary methods of processing steel and metals used in every industrialized nation of the world
Henryk Zygalski - designed the "perforated sheets," also known as "Zygalski sheets". Variation of these were used for a couple of decades in computers.
Jacek Karpiński- responsible for the construction of the first transistor-based differential analyzer and for the development of one of the first machine learning algorithms and techniques for character and image recognition. He is also the designer of one of the first minicomputers - the K-202. The computer was ahead of its time and probably the fastest.
Wiesław Romanowski- the first commercially feasible rendering software system called ARTS (Accelerated Ray Tracing System), based on ray tracing technique.
Andrzej Trybulec - developed the Mizar system
Jan Węglarz - discovered the so called two-phase method, but unfortunately he published his discovery in a Polish newspaper, so it was ignored. Western scientists received accolades instead. He refused many offers from the west and opted for his own research team in Poland.
Michał Zalewski- one of the tope "white hat" hackers.
I'm too lazy tonight to post names of Polish mathematicians whose work make a lot of computer advances possible. I'll leave that exercise as your homework. I am certainly not interested in computer games, with their half life of about a year or two.