Are home prices too high?

From Kimberly Burnett and James Jones at the University of Hawaii Economic Research Organization:

We start with very simple assumptions: a required down payment of 20% and an income in which 30% or less would go towards housing. In May of this year, the median single family home on Oahu was $630k and the median condo $315k. In our calculations below we assume a mortgage rate of 4.0%.

At current interest rates, if your dream is a single family home, you will need $126k to put down initially, and an income of right over $96k. Your monthly payment would be in the neighborhood of $2,400. If condos are more your style, your down payment would be in the $63k range, and you’d need an income around $48k. This leaves you with a monthly mortgage of $1,200.

Is that affordable?