50% of the sound you hear in a well designed listening room is indirect--bouncing off other surfaces.
It certainly is.
This is why it is so important to select speakers with an even power response and good horizontal dispersion (with similar off axis response over the entire frequency range). This way your room is loaded correctly and the reverberant sound field remains balanced along with the primary signal directed at your ears.
A speaker with uneven power response or very narrow dispersion will have a very limted sweetspot and will be highly sensitive to placement => it will likely only sound good in one spot with one listening position. A good speaker should mean that it sounds balanced around the entire room.
Room treatments will still be essential but much easier to employ if the speaker has an even power response, as the main issues will be bass trapping and some reduction in nearby first reflections (anything that beams sound at the listening position like a wall too close to the listener or speaker)