Well, it's also a cost for private society:

Imagine you're an IT contractor that needs to bill international customers for your services. In Italy you have to pay very high taxes since being an independent worker you fall in the same category of those who can easily dodge taxes although you're not in exactly the same position: the government treats you as a thief by default and puts you up to a taxation level that makes sense only once that it's assumed that you will only declare about half of your revenue.

This is actually a big problem and has severe repercussions on the ability to spawn new businesses in Italy.