Through the years of the crisis, it has been proven that overtaxation and foolishly high rates of social security contributions lead to the legitimization and the growth of the black market.
Rather than solving the problem of tax evasion, it is making it even worse as there are entire professions that have realized they cannot survive within the system.
Governments that have presided over the crisis in Greece have appeared to not understand this. Maybe and quite possibly that is because they would prefer to ignore how the real economy operates rather than do their research and tackle the problem effectively.
What is surprising, though, is that even the technocrats from the institutions our lenders are comprised of choose to ignore this reality.