there's a reason however: the limitation comes from our constitution and changing that requires a supermajority that hardly any government had in the last decades.

Art. 34. La scuola è aperta a tutti. L'istruzione inferiore, impartita per almeno otto anni, è obbligatoria e gratuita.

"(public) schooling is open to everyone" "primary instruction, covering at least eight years, is mandatory and free of charge"

there's both the right and the mandate to get all children into school, changing that is something that has been evaluated and still under discussion because it will be very hard to put an amendment in there that's both general enough to cover the issue at hand but not so generic that it might be exploited in the future.