This time I was about to comment early as we are roughly in the same timezone ^^.
PhD are very useful. They form people to think about a very hard problem and solve it within a couple of years. This leads to people very useful to the society, even if they will eventually work in a different domain. They have the experience in working very hard on a given issue and solve it, even if it takes years. The right point being: do we need thousands of such people. As you said: a society cannot work with 10% of managers.
A funny thing at least in some countries, is that some people are indeed complaining about these foreigners taking away jobs from the native workers, but at the end of the day, they take away jobs that the native workers do not want to get... And then come the rise of extreme-right wing parties... It is hard to understand to me. Many people simply do not think here. This being said, I am a bit scared by the outcome of the future elections in France, as a foreigner living there for more than 10 years...
I have the utmost respect for PhD's such as yourself, without a doubt tackling a very difficult problem for many years is a quality that proves to be extremely useful. But as you said, we don't need everybody to be PhD's, but with degree inflation, it can't be ruled out that things will converge that way some time in the future.
Part of the problem with native workers rejecting jobs they don't want, is the mindset that certain jobs have more or less importance. It has a lot to do with prestige and "face", something highly industrialised nations face now more than ever. The sense of entitlement for the best paying jobs as a fresh graduate is unhealthy because it undermines the aptitude of those who are performing just as well on the job as those who have no experience.
I'm not sure what will come about in the French elections, but I would guess that much like other times of uncertainty, particularly with the backdrop of the Euro showing signs of failure, there will be a rush to safe haven assets, perhaps gold, the yen, even bitcoin.
I definitely agree with this analysis.