Ah, right. That would be unemployed 'musicians', sitting alone in their bedrooms i suppose. I concede that under those circumstances, having an amp head that's marginally wider than a speaker cabinet might be a red hot issue. Ya gotta be lookin' good there for the posters on the wall I guess.
Conversely, someone who actually takes their gear out and plays music in an attempt to entertain people in some way is probably more concerned about other minor details, like ... err, I dunno ... sounding good and playing well, and in context. You know, minor insignificant details like that.
I get to play out regularly to ordinary, regular folk. I go to jams with other players in various settings, public and private. Players and listeners often come up to me and make comments ... about my sounds, playing and the effect it has on them. Their comments are always positive and enthusiastic (although i could also accept negativity in such comments, I'm not so stupid as to think that everybody loves me or what i do). But the point is that what my gear looks like (or what i look like like, for that matter) to me is totally insignificant, and it is never mentioned by people who make comments to me. Never.
Of course there's room for people to be concerned about what their gear looks like, or how they look when they're playing.
But that has absolutely nothing to do with learning to play, playing at an intermediate or high level, entertaining, slotting oneself into a musical situation, trying to connect with others via music, getting good sounds or anything else to do with music. It's simply a pointless vanity.
But that's only my worthless opinion. At such time as the physical dimensions of my equipment becomes an issue for either myself or the listeners, I might need to review the situation. I guess in the meantime i'll just have to struggle along, apologising to the listeners ... "Thank you for the compliment, I'm glad you found something in there to enjoy this evening. I think i would have played better, and you would have enjoyed things much more, if i'd made my amp head just an inch narrower."