I highly recommend comparing these numbers for Poland with numbers for other European countries. You'll find that Poland is on the cheaper end of the employment cost spectrum - that 40% figure (which is actually 38%) only refers to the cost of employing a minimum-wage worker, and it's not 38% that's taken home, it's 38% that's taken by government, and it's still lower than EU average.
As personal and corporate income taxes in Poland are quite low (again, compared to other European countries), combined with the fact that labor in Poland is extremely cheap (in EU, if I remember correctly, the labor is cheaper only in very poor countries like Latvia, Lithuania or Bulgaria), employing Poles and doing business in Poland is very cheap. It's very illuminating to compare the percentage of corporate income spent on worker wages in various countries -- companies spend very little on employees in Poland in general.
As personal and corporate income taxes in Poland are quite low (again, compared to other European countries), combined with the fact that labor in Poland is extremely cheap (in EU, if I remember correctly, the labor is cheaper only in very poor countries like Latvia, Lithuania or Bulgaria), employing Poles and doing business in Poland is very cheap. It's very illuminating to compare the percentage of corporate income spent on worker wages in various countries -- companies spend very little on employees in Poland in general.