Is there a reason to think they are
not the result of automation? Take a look at [1] - robots brought into US factories are directly responsible for lost jobs and lower wages. And I think you must be pointing to a state of affairs that hasn't been true for at least 40 years - look at the chart in [2]. I'm not interested in what may have been the case 60 years ago in post WWII boom-America, I'm interested in what the trends have been during the lifetime of the average reader here.
As for self driving trucks, who told you that? Per my prior comment, we're not there yet, but it is definitely coming. Automation hasn't reached driving yet and it won't in any significant way for at least another 5 years, but as soon as the tech is ready, adoption is going to be rapid. But saying "it hasn't happened yet, so clearly it's bogus" is like building a cabin on an active volcano and saying, "they said it would erupt within the last 5 years and that didn't happen, so clearly it's not going to erupt ever". Just because a predicted timeline is incorrect does not mean the predicted event won't come to pass.
[1] https://www.recode.net/2017/3/28/15094424/jobs-eliminated-ne...
[2] http://evonomics.com/productivity-is-slowing-inequality-is-g...