Tax evasion is a public pastime not just in Greece, but in many European countries, and is not restricted to just the wealthy. I sometimes wonder whether the vicious cycle of lost receipts is the reason for high taxation, leading to more evasion. On the other hand Scandinavians seem content with very high tax. Why is that? Is their money being spent equitably, transparently and with consent? It seems to me the larger economies have too many competing interest groups making consensus much harder to achieve.
Another problem is that Europe is not homogenous, so cultural differences can be big. Expecting Greece to adopt the disciplines of say the German economy is going to take a shift in mindset. The fundamental difference between all countries used to be the relationship between banks, businesses and governments. The question now might be has globalization brought about more of a uniformity in that relationship.