Why have buildings of siena been preserved not modernized?

Buildings in Siena have been preserved rather than modernized primarily due to the city's rich historical significance and commitment to maintaining its medieval character. Siena's well-defined urban planning and stringent regulations protect its architectural heritage, ensuring that any renovations respect the original designs. Additionally, the city’s status as a UNESCO World Heritage Site emphasizes the importance of conservation over modernization, allowing it to retain its unique charm and historical integrity. This preservation fosters tourism and cultural pride, further incentivizing the maintenance of its historical buildings.