You are right that most people lack the ability, I am the same way. However as I get older I’ve found it more and more difficult (not impossible) to perform those visualizations. I don’t know if I can attribute it to just age or the various alcoholic beverages I’ve consumed over my lifetime. I live a very healthy lifestyle and I know that helps but it is very unnerving to feel like a treasured skill may be waning.
The ability to visualize the entire system has prevented so many coding disasters over my career I couldn’t count. Hopefully you don’t experience the degradation like I have but unfortunately it might be a unavoidable certainty.
I am sixty nine now and the only skill I use for income any longer is talking on the telephone. I certainly don’t have the full mental abilities I had at 18 but I can still visualize. I can actually recall details of a stream valley on the little farm where I grew up even though that part has been under a fish pond for nearly fifty years now. I can see the steep slope I used to ride down on a draft horse when I would unhitch him and ride him back to the barn at noon when I would feed him and go and eat my own midday meal. I had to be very careful not to slip forward onto his neck as I was riding bareback. He was so big with such a broad, flat back that my legs could barely hold onto him, I was a preteen at the time, maybe eleven years old. The horse was jet black with a white diamond on his forehead and white stocking forelegs with the long white hairs, much like the first team visible in this video.https://www.youtube.com/watch?v=ZErW1QoAn1w