I don't know if there is a concrete source of your claiming.
Even if there is, it's probably restricted to the USA.
At relevant parts of the USA, house sizes are being compressed.
Source: The New York Times
Title: The Great Compression
Date: 02/17/2024
Link: https://www.nytimes.com/2024/02/17/business/economy/the-grea...
Edit: formating