The record breaking ones are often vanity projects first and built with profitability in mind second. They're so big they are hard to fill; their architecture

The record breaking ones are often vanity projects first and built with profitability in mind second. They're so big they are hard to fill; their architecture and floor plans are built with potential tenants as an afterthought; and because they are built at high cost, their mortgages demand premium rents that may be out of line with the general office market. --- You build a vanity skyscraper against the cycle at your own peril. The downfall of Sears is sometimes correlated with the opening of the Sears Tower in the '70s.