It has nothing to do with the technology level.
People have been saying since the days when Superman still changed his clothes in a phonebooth that secret identities made no sense and would quickly get found out. It's always been one of the biggest criticism of superheroes, right up there with why does everybody look so good in tights?
At some point people just started refusing to suspend their disbelief. I just chalk it up to being one of those annoying "oh no. Superheroes are serious. they have to be realistic" bits of nonsense people blather on about so as not to have to admit they enjoy something that was designed for little children.