> It was such a simple concept but it worked so well. Wouldn't be able to do something like that anymore due to all manner of sandboxing in action. Lost a tool, gained security.

This class of programs absolutely still exists (see: every debugger, scanmem, GameConqueror, etc.).

Sandboxing doesn't prevent processes from inspecting the memory of other processes, it just prevents the sandboxed process from doing things it shouldn't.