Boomers (b. 1946-1966) bought houses long before they were $70k. Assuming a great job straight out of high school, the first ones would have been buying homes as early as 1964, the last boomers by 1984.

Taking the middle - 1974 - and in my neck of the woods the median 1974 starter home was about $16k CAD, and the minimum wage was $4k/yr. This put even minimum wage workers within spitting distance of the flip side of the one-third rule, which states the price of a new home should not exceed three years of income. Workers in good industries - such as framers, plumbers, and electricians - easily met this 3× rule even within a year or three of starting work.

So the better phrase would be:

boomers bought houses at $16k when they were making $6k/yr