Why geography and preservation constraints affect Italian naval bases

Why did Venice, Genoa and Pisa lose naval importance relative to ports such as La Spezia and Livorno?

Geography, access for large ships, security and refuelling needs matter, while preservation rules can constrain work in historic ports.

A naval base needs approaches and facilities suitable for the ships it supports. Likely threat directions and the ability to protect a large ship influence the choice. Access to refuelling is another practical consideration. Historic ports can also have rules intended to prevent damage to their older fabric. Preserving that history is understandable, but the resulting restrictions can make a location less practical as a naval base.