Exactly, seems like the Von Neumann machine assumption is outdated, especially with modern supercomputers. Memory access itself isn't O(1), it's more like O(N^(1/3)) because space is a serious consideration, and that's your distance from a focal point to all other points within a 3D volume.
Yet, memory access can be limited by latency and bandwidth. Predictable access patterns (e.g. linear scan) tend to enjoy prefetech reduces the latency of accessing random parts.
