Median earnings in 1970 were closer to 56k in today's dollars. 1970-1980 was a recessionary period, followed by stagflation in the 80s. I hate when people use that time period as an anchor to show growth. It's like using 2009 as an anchor.
Still, real wages in 1975 were relatively high compared to previous decades. See table A-7 here: https://www2.census.gov/library/publications/2024/demo/p60-2...
Estimated median earnings for full-time male workers peaked in 1973 in the chart, until surpassing it in the 2010s. It's hard to find directly comparable data for earlier decades, but estimates put wages significantly lower. If you anchored to the 1920s, 30s, 40s or 50s instead, you'd just show even more growth in median wage. If you're saying we shouldn't compare to the 70s or 80s either, then what's left? Just years after 1990?
Not sure how you're getting 42k: https://www.minneapolisfed.org/about-us/monetary-policy/infl... spits out 51k for that number.
In either case, IMO, +-10% over 60 years should just be considered flat. Calling it flat is probably generous considering how inflation has affected durable goods vs necessities. We can buy more appliances now, but places to put them have never been more expensive relative to income.