From the US standpoint, Germany has very little comparative immigration. I understand there are many German citizens from surrounding nationalities, but I don't think that it's quite like what we have.
I do understand the issues and difficulties the Germans faced during reunification, and the economic issues with such a merger. This is for similar reasons as to why it's difficult with America: We are constantly merging new people into our culture that have very low paying jobs, and little education (ie, illegal Hispanic immigrants), which compare to the merger of a demolished East German economy....This causes a constant offset in the improvements that we attempt to make in other areas. For example, African Americans have made huge strides in the past 30-40 years in terms of education, and the economic gap between their racial group, and the European majority that makes up our population. Despite this, we have offsets in other areas due to illegal immigration.
Furthermore, I don't think many citizens would disagree that it's the governments job to ensure equality for it's citizens. The major crux of the libertarian/conservative critique of equality is that the government shouldn't subsidize equality by taking more from the apt to pay for the inept. Universal healthcare? Not a bad idea. But in America, should we have such a system, we would have close to 15,000,000 illegal immigrants utilizing such a service that do not, and will not pay for it...So those in the middle & upper class face even more progressive taxes to offset the inequality of those that don't pay taxes.
Oh, as for the immigration: I was referring to the CIA factbook concerning racial compositions in your country. In Germany, the majority culture (those of European/German descent) make up 91% of your country. In America, it makes up ~60% and rapidly falling due to influxes of illegal immigrants. Because of this, we are weary to let government force socialism on us. It's not that we do not want healthcare for everyone - it's a great idea - but the argument is who pays for it, and if there's a monopoly on such an institution. In Social Security's case - our federal pension plan - the Government was the soul institution that managed it, and has ruined the system by proving atrocious below-inflation interest rates: Pay in $2,000 today, get $1,900 back once inflation is taken in to consideration. Until President Reagen came into office, there was no other system. Now we have 401k's that provide 10% and above, depending on your plan.
Ultimately, it comes down to the size of government, and the social composition of where your at. I understand the European model, and I think it's great....It works for Europeans. But port it to 1 government that equals the size of many of your countries, with a much larger skewing on the GINI index (far less equal), and it becomes a much more difficult situation to deal with in an American model. Therefore, us conservative/liberitarians want a better hybrid solution: Have universal pension, healthcare, education, but don't give the government a monopoly, as our government is more corrupt than yours.