https://www.bleepingcomputer.com/news/microsoft/microsoft-old-windows-updates-now-expire-to-improve-speed-security/

Microsoft says it regularly evaluates Windows updates for expiration to make the entire update process faster and safer by removing older releases that have already been superseded by newer packages.

Installing updates is slower and their size gets incrementally bigger due to the long backlog caused by the two or more updates for each Windows platform released every month.