Spaghetti and meatballs isn’t an Italian dish 
But Naples, we have something better: “The cuzzitiello”! It didn’t start as street food It was a habit at home, almost always on Sunday morning, while mum or nonna made the ragù, the hungriest person in the family would take the still-warm “pane cafone”, pull out the crumb, and fill that crust with sauce and meatballs That heel of bread became a bowl Today, it is one of the classics of Neapolitan street food
In the past it was food for poor families (yes, nothing of more expensive attractions like cheese or meat). But today , at the current price of bread, it ceased to be such.
ETS and other EU communist regulations are forcing people to rethink their traditional cuisines. Also the diet for fast periods.
For example, fish was the most popular component of the Catholic fast in Europe. But, now euro-communism made fish a luxury product. It is visible e.g. in Poland when it comes to the Christmas Eve fast dish - carp. Carp was one of the cheapest fish/meal in socialist Poland. But now, the prices - especially if you want to buy local carp not imported one, are comparable with... venison.
Thus, carp, becoming quite luxurious, lost all its sense as the dish for the fast.
On the other hand, the sellers still think that nevertheless people will buy the product due to the sentiment from the childhood or whatever. The similar process is happening with other species of fish, even simple herrings, popular for the Lent - currently more expensive than average meat.
The cheese was not added because in the south of Italy, tomatoes are very common, while in the north, cheese is frequently used.