Oh, BS.
Maximum Social Security benefit in the US: $28,392/year.
Maximum social insurance benefit in Greece: $101,927/year.
Average Social Security benefits in the US is $14,124/year. I wasn't able to find a specific number for Greece, but I saw a news report in the past couple of days that indicated it was approximately double that of the US.
Tax rates in Greece are 7% on the employee and 14% on the employer. The next result is that contributions are about 50% higher for each employee.
Normal retirement age is 65 in Greece, 66 in the US. Early retirement age in Greece is as early as 50.
Government pensions in the US are similar to the Greek pensions, even more generous. Perhaps everyone in Greece is considered a government employee so they have more generous pensions.