> I wouldn't even consider it without fluency in Italian.
For the affluent, obtaining a second passport though e.g. citzenship-by-investment programs is all done through intermediaries. You pay a law firm a few tens of thousands of euro and they take care of everything – the only action required from you is going to an office to pick up your passport at the very end of the process. Since these affluent individuals are so used to relying on expert assistance, no knowledge of the local language is ever really necessary.
For less affluent people, especially those obtaining citizenship through ancestry, there are sometimes requirements to prove a B1 command of the local language, so in that case actually learning the language is a must.