Most likely because old buildings are expensive to maintain, expensive to heat, must be refitted for modern lights or communication or have asbestos or lead pipes or don’t comply with modern building standards, such as accessibility.
There is this old cinema from the 1920s in my town that went out of business in the 1990s. Nobody goes to the cinema anymore to fill the 300 seats, it’s a 20min walk away from residential areas and there is no parking nearby. On top of that it needs 30 years of maintenance. Nobody has a good business plan for this building.
He probably bought it in the 70s when he had no kids and his salary was higher, compared to the 80s and 90s with inflation, but the same salary.