From the Atlantic coast to Russia, what is the main reason why the walls of traditional European houses are getting thicker and thicker?

The main reason why the walls of European traditional houses are getting thicker and thicker from the Atlantic coast to the east is the influence of temperature.

The Atlantic coast is affected by the westerly airflow and the North Atlantic warm current in winter, and it is warmer in winter. The influence of westerly airflow from west to east is weakened, and it is difficult for the North Atlantic warm current to affect inland areas. The average temperature in winter in the eastern region is gradually decreasing, and the climate is cold, so the walls of houses need to be thicker and thicker to keep warm.