[lsh123]

"Labor productivity has been in long-term decline"

If I read the graphs from the link correctly, they show that % productivity growth is declining. Still it is positive thus the productivity by itself continues to grow. Hard to say from the graphs, but it looks like absolute productivity growth per year is bigger (or at least the same) as in the 50's: avg 2.5% growth over 60-70 years means ~5x increase of absolute value, thus 4% / year growth in the 50's is the same absolute value as ~0.8% growth today.