From my 3rd most favorite economist,

This Is One Reason Why Trump Bringing Foxconn Manufacturing Jobs To Wisconsin Is So Important

Movement from higher paid jobs to lower paid jobs by Gary Shilling:

"In this economic recovery, the jobs that are being created are mainly in low-paid work. It’s been in sectors such as retail trade, where real wages have risen just 0.9 percent in total since the beginning of 2007. Similarly, the 3 million increase in hotel clerks, waiters and other leisure and hospitality jobs in this recovery has far outstripped the 900,000 gain in manufacturing. 

In June, manufacturing employees were paid $26.51 per hour, compared with the $15.43 per hour earned by leisure and hospitality workers. In addition, manufacturing employees worked 1.56 times as many hours, so their weekly pay of $1,081.61 was 2.69 times the $402.72 paid to the average leisure and hospitality employee. Even within industrial sectors, wages have been restrained as postwar babies at the top of their pay scales retire and are replaced by lower-paid new recruits."

Gary Shilling Blog