Agreed. I think the reasoning for arranging across the shorter dimension is 2-fold: 1. potential for improved bass by locating the speakers further from the front wall and the MLP from the back wall and 2. Improved integration with side-wall reflections.

The problem with my place is whoever architected it 55 years ago, must have had a hate-on for audio. In the living room, setting up along the length is all I could do and for various reasons, it sounds better than along the width.

Between my living room and the basement, I have two different listening environments. Upstairs is intimate and downstairs it's a much larger and spacious sound.

BTW, I can't do what you did at your place, Phil. My speakers and MLP need to be positioned just so because I don't listen casually. I've tried portable speakers for the deck for example and I can't get into it because a) the fidelity is not there and b) I can't position them to evoke the emotion I desire.