the point is that the number of jobs themselves do not dimish
I agree there. Think of the jobs that have been lost over the years as stores have closed due to competition from the internet. During my lifetime, I've seen independent bookstores merge and disappear, and even the mega-chains go away (e.g. Borders). Music stores - gone (Tower Records, Wherehouse, Sam Goody). Video rental - gone (Blockbuser). Big box electronics - going (Circuit City, Good Guys, Tweeter).
Despite all of this, unemployment stayed relatively constant, aside from the spike during the recent economic downturn (and these jobs were not lost as a result of automation).