I think the title to this thread overstates the issue. Obviously the room is very important, but it's only a make or break situation if the listener makes seriously unwise choices in loudspeakers. It involves trade-offs. If you want full range and loud you will need to utilize acoustical treatments. If you only listen at moderate levels and you're willing to sacrifice some deep bass, then you'll need less treatments, if any. Additionally, if you set up a true near field arrangement you can greatly reduce the need for acoustic treatments. Plus, there are loudspeakers that are actually designed to control and/or reduce room interactions. Gradient, Snell, Klipsch, Kii, Lyngdorf and others have some interesting designs. It's more subtle than the thread title indicates.
"The room can totally wreck, or make, a system"
For those interested in dealing with the most important part of their system -- indeed, the precondition for a good system: the room.