It has very little to do with trust and a lot to do with the realities of hardware implementation. Every interconnect has a minimum linear transfer granularity that properly utilizes its hardware links, dictated primarily by its physical link width and minimum efficient burst length. The larger this minimum granularity, the faster and more efficient moving data becomes. However, below this granularity, bandwidth and energy efficiency crater. Hence, reducing access granularity below this limit has disastrous consequences.

In fact, virtual memory is already a limiting factor to increasing minimum transfer size, as pages must be an efficient unit of exchange. Traditional 4 KiB pages are already smaller than what would be a good minimum transfer size; this is exactly why hardware designers push for larger pages (with Apple silicon forgoing 4 KiB page support entirely).

I cannot help but feel that many of these discussions are led astray by the misconceptions of people with an insufficient understanding of modern computer architecture.