This is largely not the case in my experience. They probably understand the lower level details of manipulating memory better, but there's a lot more to developing software than understanding that memory is a specific place.
Yep, and all of that is derivative from how to organize memory. Classes are just more fancy structs. Object creation is memory initialization. Processing flow and code reuse is recognizing memory access patterns. ETC and so on.
This is wrong. Lots of algorithms behave completely differently based on memory layout. There is typically an inflection point where big O effects start coming into play, but at most scales, memory locality tends to be way more important in determining how efficiently something runs.
If your algorithm is poorly designed and does significantly more work than necessary then that is independent of physical memory.
It's like you are trying to misunderstand me.