In their NYT piece on the possibilities for people switching jobs mid-career, Clair Cain Miller and Quoctrung Bui link to a piece by M.I.T. economist David Autor to support the assertion that extensive research shows middle skills jobs are disappearing. Actually, more careful research showed the opposite. In the last decade, both middle- and high-skills jobs (using Autor's definition) were declining as a share of total employment. Only the least skilled jobs had an increasing share.
It is also worth noting that there is little evidence for the "skills shortage" discussed in this piece. While businesses like to complain about not being able to get qualified workers, the ordinary response to a shortage is a rise in price. In other words, if businesses really were seeing a skills shortage, we would expect to see rapidly rising wages for significant groups of workers. We don't, which suggests that businesses are just whining because they think it will help them get something from the government — not because they actually can't get qualified workers.