In particular if the success of something you opposed seemed inevitable, you'd still oppose it.

Oppose in the sense of "actively work to stop it" or oppose in the sense of, "if asked about it, note that one dislikes it"? I dislike the increase of surveillance over the decades but look: Sensors get cheaper year by year. Computation gets cheaper year by year. I'm not happy to see more surveillance, but I see it as so close to inevitable, due to the dropping costs of the enabling technologies, that actively opposing it is a waste of time and effort.

To put it another way: In the original C.S.Lewis quote, Lewis includes in his own list of questions that he wants asked: "Is it possible?" I view most of the questions that Lewis disapproves of as just being ways of asking whether recent historical evidence make something look possible or impossible in the near future. In my view, usually, claims of historical inevitability are overstated, but, occasionally (as in the cheaper sensors example), I think there are situations where a fairly solid case for at least likely trends can be made.