IMnsHO, this is a crucial observation.   The virtual memory manager is always “lazy.”   If the memory is available, and if there is no “pressure” actually being exerted upon the virtual-memory resource, then the VMM will make absolutely no effort to clean up.   After all, it is perfectly plausible that, someday, you might ask for that same bit of information again.   It is to the system’s advantage to presume that you will do so.

VMM’s are designed to respond only to actual memory pressure.   Like a typical bachelor, it won’t load the dishwasher until three minutes before its girlfriend is due to knock on the door.   And, on our typically fast and typically capacious “developer” machines, that rarely happens.   (Memory pressure, I mean ... not girlfriends.   We hope.)   Consequently, memory requirements are customarily reported too large.