droplets of water are not lenses without a glass behind it, and we couldn't see substantial effects behind them before we had glass windows. There was little evolutionary reason to develop any perception of refraction in droplets of water. in contrast, shadows are instant indicators of distance and gradients instantly distinguish concave from convex surfaces for light coming from above.
I get that your point is that we don’t have a strong intuition for lenses and that’s tied to a lack of evolutionary reason to have them. I agree and suspect that might be the point of why Apple are using a the lens effects. We don’t need to go so far as to say the natural world is completely devoid of such phenomena. Of course they’re there but they’re largely not relevant to survival throughout human history
(water doesnt do lensing unless it s a droplet)