In my opinion the idea that time is responsible for the difference here is wrong. Sociological science fiction has its root in weird tales, oldschool horror (village of fish people worshiping elder gods, anyone?), and adventure stories about tribes of cannibals and witches and such. Consider the mythological amazons who lived without men - that's sociological sf right there. Faeries too have a strong tradition of thinking in a non-human way. The idea of using gadgets and mechanical inventions got into the act with Poe and Hawthorn, who were influenced by inventions of things like shock "therapy" and clockwork toys. All of it is older than Asimov. Sociological SF and gadget sf are two subgenres that exist alongside each other and can be combined; neither replaces the other.So far, it sounds like a big part of the change since Asimov wrote that is what kind of ideas, SF is a literature of. In his day you could have stories focusing on a single piece of technological or scientific change. Nowadays, the ideas are already social innovations. So that what was for him the most sophisticated form of SF is for us the ground state of what an SF story needs to have, a change in human society and the implications thereof.
Does that sound right?