I personally think the "match your bar width to your shoulder width" conventional wisdom makes no sense. I've done many long rides and multi-day tours on very wide drop bars like my 46cm Rene Herse bars, and more recently my 53cm Crust drop bars. I'm 5'7, 140 pounds. No shoulder, wrist, or hand issues whatsoever. I've even done a couple multi-day tours on slightly swept back mtb bars with no shoulder issues. Some predictable wrist issues, more due to lack of hand positions than width.
What I did gain from the wider drop bars was better handling on unpaved ATV trails, rail-trails, and singletrack, as well as more room for handlebar/randonneur bags.
I think it's mostly what you're used to, and what you get used to. Riding on a 38cm bar feels unbearable to me now. If I had to do it for a couple weeks I'm sure I would get used to it. A couple years, I'd probably prefer it.