If you are at the bottom of the American labor heap, you
have never faced competition from machines, globalization,
and immigration like you have now.
That's begging the central question. The biggest leaps were made long ago. The invention of electricity, the steam engine and the combustion engine, those enabled automation on a scale that was truly never seen before. Then there was slavery: that's competition from globalization/immigration if there ever was. China, India and the other low wage countries are getting higher standards of living fast, so their wages go up and their competitiveness down.
I strongly question the assertion that we are currently losing lowskilled jobs to automation or competition at a faster pace than in the past.
Of course, the pace of loss is not that important - if there's sustained net loss, sooner or later, we will reach zero.
Also, I'd argue the biggest leap is computer technology, and it's having a lot of impact still. My guess is bio-engineering is next. If that happens (and it's a big if, in my book), there will be even more impact.
So, going back to the point, my original assertion was we're slowly running out of low-skills jobs. That's backed up by pretty much any look at employment figures. Manual labor has been wiped out to an insane extent (agriculture is what, 3% of the labor force now?). And the service industry is next, IMHO. Retail is slowly bleeding to death, for example.
I strongly question the assertion that we are currently losing lowskilled jobs to automation or competition at a faster pace than in the past.