DaasYochid: Escalators, Shabbos elevators, public transport trains and buses and other such contraptions-say a moving floor like you have in airports- “min hadin” should be muttor. One who uses it does not make any act, he does not push buttons, he does not move levers, he does nothing. I cannot see how this can be ossur “min hadin”. You have to show me what such an individual does to be under the heading of a “melocho”. However, because of external reasons- say “maris ayin”- certain of these actions-public transport- have been discouraged. Escalators or Shabbos elevators-not being subject to such problems- have been allowed.
The above is simple and makes sense. Anything else seems to be a chumroh.
I could not read the “shoeil umehsiv” in your excerpt-print too small, so I do not know whether he uses the term “zilzul Shabbos”.
However, these words of yours: “Poskim in each generation are applying the concept to new applications” explains your view. it also explains my view- that some of these are new concepts made anew and which have no basis in Halacha.