But if I wouldn't speak english, I had to read german news only or couldn't use stackoverflow. 90% of the newest technology would be useless for me, because I couldn't read any documentations or tutorials.
While my spoken english isn't very good I'm able to read advanced technical books, manuals, news, and other texts without any problems.
I rarely have the opportunity to speak english. That's the problem.
From my (potentially quite flawed) understanding, English, French, and German are all good languages for capturing technical concepts, but English won out in general, simply because it's much bigger - more native speakers (thanks USA) and more widely spread (thanks British colonialism).
"... German advanced to become one of the most important languages of science and scholarship, and at the beginning of the twentieth century ranked above English and French, especially in the sciences. In order to keep abreast of the latest developments, scientists and scholars all over the world learned German, a circumstance that contributed to German’s becoming one of the most widespread foreign languages. With the end of the First World War, the “primal catastrophe” of the twentieth century, a reverse tendency arose. Germany and Austria had been economically ruined by the war and were in no position to invest in research and knowledge to the same degree as before. ..." (from http://www.goethe.de/ges/spa/pan/spw/en3889454.htm )
I'd suppose the closest thing to a nazi-controlled-germanized-europe would be the USSR (people escaping, restrictions on freedoms hindering creativity, no colonies speaking the same language, trade issues with the rest of the world) which in fifty years failed to establish a linguistic dominance even in aligned countries.