US population growth and GDP
1975 - 215m - $1.6 trillion
1985 - 237m - $4.3 trillion
1995 - 266m - $7.6 trillion
2005 - 295m - $13 trillion
2015 - 321m - $18 trillion
With population growth, people need housing. US economy has grown from 1.6 trillion in 1975 to around 20 trillion in 2018. All these can expain why housing prices are going up, even though your charts show that the real wage growth is 0. Another reason for home price going up is that we have not built enough housing to keep up with US population growth.