I'm sorry, I really don't know enough about the Italian Wars to agree or disagree with the assertions made regarding those.
In so far as 'not into colony building,' most of the responses had made it sound very much like national endeavours, when I don't feel that they needed to have been. If I may quote from another post:
The English colonies grew up more or less organically (as various religious groups set up their own settlements in New England and Maryland, and a few other speculators founded colonies in more or less the same way today's rich buy baseball teams); they mostly weren't the result of a major, intentional colonization project on the part of the Crown.
In a great many instances of colonization, they were individual or small-group actions taken with *permissions* of the government. Georgia was given to Oglethorpe for debtors and small farmers, Singapore was built By Raffles as part of the East India Company. India was originally an East India Company operation until the Sepoys.
I'm not claiming or asking why Venice, Genoa, or any of the other Maritime Republics didn't colonize the whole of the Americas or India or whathaveyou, but (naval architecture notwithstanding) I don't think it would it would have been a crazy thought for Venetians, Genovesi, etc. merchants and businessmen to establish a small colony in the West Indies (for example, Curacao or the (Danish/American) Virgin Islands. I dunno, just tossing examples out. No need to tell me why those specific examples wouldn't work), or a Singapore or Batavia in the East Indies. Heck, even Austria colonized the Nicobar islands and their ports were just as far away as the Venetian ones, and the Duchy of Courland way up the Baltic colonized Tobago, and the Maltese were even in on the colonization game. No, they don't need to set up the vast plantations of the Carolinas, Virginia, and the Subcontinent, but trade hubs and markets dealing with the people who are the original supplies of the good their trading makes good business sense. . . and if a few want to set themselves in position to /become/ those original supplies, so much the better.
I still feel at the end of the day, the primary factor was the reliance on galleys, though I'd like to get inside the heads of the merchants, businessmen, and venture capitalists of the Maritime Republics and say, 'Hey, why don't you outfit a few ocean-worthy vessels and find the source of the riches yourself rather than relying on the Middlemen?' As the Portuguese did and the Spanish attempted to.