Copying natural laws in our work is something that was obvious for humans for millennia. We've been imagining space ships 100 years before going to space but simulating inertia for an object "sliding" on a screen was "not obvious at the time"?

Of course it was! How to do it (well) may not have been obvious but the idea of doing it was there for anyone using a computer. The parallel with the real world was always obvious because this is directly analogous to how physical objects behave and you'd do naturally in the physical world. The world around you provides the "observed example", not other computer implementations.

I personally thought since decades ago about this kind of inertia while scrolling through lists or dragging things. I thought of transparency, skeuomorphism, writing on touchscreens, etc. long before they were implemented because computers could handle them. And I can assure you I wasn't the only one.

"Same thing that you've been doing for ages in real life but now on a computer".

P.S. I'm thinking of a holographic/VR 3D interface right now that replicates interactions with physical objects either by manipulating it with my body parts, with electronic input devices, or with a BCI. I hope I live long enough to read an internet discussion where someone claims this was just not obvious back in the dark ages of the early 2020s...