It probably is, at first. But in an economy of different parties, who produces more needs some buyers to keep growing. If there are not enough buyers, overproduction and economical collapse will knock at the door. You can see this trend internationally: we seldom see a country be an outlier in the yearly growth. Either all countries grow, or all countries decline. It is the % that changes. We saw this during the 2008-2012 crisis in particular.
It is in the interest of the richest areas to help the poorest. By doing so not only the average quality of life of a country increases. With less economical inequalities between regions, the once poorer regions are buyers of goods of the once richer ones.
While you correctly associated Lombardia and Veneto to Germany, you forgot to mention that after the WWII, Germany went split politically and economically. When it got re-united in 1989-1991 East Germany was economically very diverse from the more developed West. Our fathers were wiser: instead of doing referendum demanding taxes to be withheld in the West, they demanded to be taxed to help the East. [source https://en.wikipedia.org/wiki/German_reunification#Cost_of_r... ] After 20 years those differences are still somewhat visible, yet they do not constitute a problem for Germany's growth and quality of life as a nation.
On the historical side it has been confirmed that 2/3 of the gold resources in Italy came from Regno delle due Sicilie [source: https://it.wikipedia.org/wiki/Regno_delle_Due_Sicilie in Patrimonio e finanza section ]. Those lands are today's most rural parts of Italy, yet contributed the most to the wealth of Italy as a nation.
I highly suggest a read on this last historical matter: Terroni by Pino Aprile. You might find a different point of view. [ https://www.amazon.com/Terroni-Ensure-Italians-Became-Southe... ]
Yes, however one still needs to decide to which extent. Italy helps the poorest areas much more than Germany or the US do. Would a federal model like Germany work better?
That's why I said that redistribution is OK in principle, but many feel that in Italy there's just too much of it.
> On the historical side it has been confirmed that 2/3 of the gold resources in Italy came from Regno delle due Sicilie
Many wrongs were commited in that age, many of which targeted the North, as well.
However, if you sum all the subsidies the South has been granted through the years (one among many: Cassa per il Mezzogiorno) that would easily offset those gold resources.
Edit: actually is more, Cassa per il Mezzogiorno was given about 140 billions, while 2/3 of Italy's gold resources are worth about 100 billions. One should also keep in mind that Cassa per il Mezzogiorno was active only between 1950 and 1984, and many other subsidies for the South were present before, during and after.
While the amount is huge, that is not event the biggest issue. What people resent is _how_ that money is spent: public construction project meant mostly to funnel money to organized crime and companies of relatives of politicians; covering the bizarre expenses of the politicians; and the never ending legion of public employees that got a job in exchange of votes (but get paid without working much or at all). If you add the fact that southern Italy is where most of tax evasion and health-related fraud occurs, the feeling for many is not that they are paying to help the poorer, but that they are sweating so that others can live a comfortable life.
While it is not a black-white situation (there are also such issues in the North, and hard working people in the South), the difference is notable.