Since the 1970’s when Madrid hit the 3 million mark with population, it would appear the popularity of people wishing to move to Madrid and make it their home went on a decline.
But this was more to do with the economy at the time between the 1970’s and 1990’s.
This phenomenon, which also affected other European cities at the time, was caused by the growth of satellite suburbs at the expense of the downtown Also affecting this greatly was the slow down in the European economy round this time.