First off I'd like to say that Western Germany doesn't live that rich if its living standards are being compared with the US living standards. In Western Germany the average salary is approximately $3000 per mouth, but in the US the similar index is about $4400 per month, but for example  in Germany,  prices at gasoline are tree times higher than in US, food are two-tree times are more expensive, but Germany got gratis education and way cheaper houses, "Medicare" is ,for free, in both counties nowadays. Well, actual situation in Eastern Germany looks pretty worse, the average salary is $1800( like in Moscow, but prices not the same). Further judge for yourselves.

I thought there isn’t any more East Germany…  It seems the unification of two German states was more a colonization of the east than creating a common homeland, similar to EU. 

The problem in Eastern lander comes from the fact that most large German corporations and isntitutions which were based in Berlin, had to left and build new headquarters in Munich, Bonn etc. From Deutsche Post to the German Patent Office, from Carl Zeiss to Deutsche Bank or Siemens....all them left Eastern lander and now hire hundreds of thousands of people in Western lander....and don´t want to go back to Berlin or Eastern lander. So, the only way Government could help is taking the Patent Office back to Berlin, because Deutsche Post is now a private company based in Bonn (last Western capital), and creating new corporations takes time. Only if the population is well prepared and creates new high tech companies (software, hardware) there could be a chance to reverse the situation. Right now, the advantage the Eastern part of Germany have are a good knowledge of Russian language, and from the Russian market which cannot be matched by Western lander, and its logistics at the center of Europe, between London-.Paris-Varsaw -Moscow. So, after decades in which the main German corporations were taken from the East to the West, and they don´t want to go back the past situation cannot be reversed...but a new one is emerging.