Important to remember that we're talking about threads and IO in one specific VM case, etc. The same assumptions won't necessarily hold in, for example, a .NET

Important to remember that we're talking about threads and IO in one specific VM case, etc. The same assumptions won't necessarily hold in, for example, a .NET case, as the memory cost of a thread is more significant (in some qualified cases). Fundamentally, most of these points have so many caveats were you to want to extrapolate them to general programming technique, that you're much better off simply saying "benchmark your actual cases and try the alternatives".