Notice that the process of elimination of the agricultural jobs was still going on in the post-World War II period. A good 10 million or so of those jobs were "automated" out of existence during my lifetime, during the 1950s and 60s -- an era now looked back on as some kind of golden age by many of the uninformed, who can see only the expansion of factory jobs during that time and not the devastation of agricultural employment. And by the way, the jobs in agriculture were backbreaking, miserable jobs that paid just barely enough to subsist when the harvest was good. When the harvest was bad, you starved, or lost your farm to foreclosure, or more likely both. Is there anyone who seriously would want those jobs back today?
Those jobs were replaced by many things, manufacturing not a small part of the total. But manufacturing is no more immune than agriculture to the processes of creative destruction. Literally every factory, sooner or later, is going to be driven out of business. It may happen because of a better process involving robots, or it may be by (temporarily) cheaper labor in a China or a Mexico, or it may be by a guy across the street with a better design for the product, or it may be that the owner dies and doesn't have a good successor, or it may be something else. The fact remains that every job will some day go away.
So what to do about that? When Ms. Zito says that "no one has any idea what to do with the under-employed, high school-educated people," she is just wrong. What to do about it is obvious. It's the "creative" part of "creative destruction." Entrepreneurs and investors, given a good business climate and the rule of law, will create and grow new businesses and soak up the excess labor -- no matter at what level of skill. That is, unless government hinders, obstructs, or prevents that process from proceeding.
The essential problem of Philadelphia, Wilmington and Baltimore is not the automation and the closure of what were once hundreds of viable factories. That happens everywhere. What distinguishes these places is that nothing has yet come in to replace the failed businesses. The problem is that the people who are creating new businesses today are not creating them in these places. Why? The right place to look is at predatory government. In these cities -- but not in others -- taxes are way too high, crime is not under control, labor regulations (minimum wage, wage and hour restrictions, favors for unions), and other regulations (including things like nitpicking "safety" and "environmental" rules) greatly increase the burden and expense of starting and operating a business. Potential entrepreneurs either go elsewhere or just don't bother to go to the effort of starting a business.
To ask an obvious question: If you had an idea for a new business that could be located anywhere in the country and could employ, if it caught on, a few hundred modestly-educated people at decent wages, is there any chance that you would choose Baltimore as your location? You would have to be out of your mind. Baltimore's murder rate is around 50 per 100,000 (New York's rate is 4 per 100,000). They had riots in Baltimore in 2015 where the citizens looted and burned local businesses for weeks on end, and the police stood aside. Is any sane investor really going to sign up to be treated that way?
The funny thing is, if you had come to my own neighborhood of Greenwich Village in the 1970s (or at least to substantial parts of it), you would also have had the impression that it was "roiled by isolation, decay and societal changes" and "ghosted by technology" -- just like the big swaths of Philadelphia and Baltimore today. The former shipping piers had been completely abandoned for around two or more decades, and the first couple of inland blocks were nothing but abandoned factories and warehouses that had formerly served the port. Here is a picture of what some of the piers looked like at that time: