In this high-tech era, the maintenance of traditional buildings in metro cities all over the globe is an expensive process. However, use of that money on making new accommodations and Highways. I am in the favor of former notion due to the source of knowledge about the history and it provides money and charity.
To commence with, the first and predominant one is that old architecture contains a depth of information. To elaborate it, old infrastructure contains a lot of history about the freedom fighters and ancestors which is important for upcoming generations, it needs to be preserved by us they can get a chance to see it by their own eyes. Taj Mahal would be the best example of it, because several books have been written on the story Taj Mahal along with this, it provides knowledge about the history and the sacrifices of over grand ancestors. Hence, it needs to be restored as a source of data.
The second most foremost reason is that museums receive money as a form of tickets and charity. To explain it, the historical buildings put charges to take a view of it, So they can able to get their expenses from it and old infrastructure receives a lot of charity from billionaires to preserve. For instance, Elon Musk donates 20 billion every year to The World Art Museum to save more old infrastructure. As a result, individuals demand to save by giving more donations.
To conclude, The restoration of old buildings in major cities around the world needs to be saved as a source of knowledge and money of charity.