But a laptop still gives you the option to go work in a park or a café. Anything taxing can be done on a remote server anyway so raw power hardly matters.
Personally I don't think I'll ever get a desktop setup.
I don't see the appeal of working in a café. It's like a noisy office, except you need to keep paying for your coffee. Might as well commute to the office where the coffee is part of the deal in my opinion.
I learned from experience that spending years at the same chair and desk can do even more damage. As part of my rehab, I switched to a laptop so I could move from couch to chair to table to standing desk easily. I also highly recommend using a motorized adjustable desk, now that goods ones are easily available and affordable. A perfectly customized height for sitting or standing is just a button push away, and I can use multiple monitors again.
There are manual height adjustable desks that can be set for near zero resistance moving up and down. They have a brake and an adjustable tension spring. I think those are the best ones. The only advantage (some) motorized ones have is the ability to remember presets.
For years I only used a laptop and I didn't really experience any of the issues you describe, I was very young though so that may have alleviated some potential issues.
I don’t know about other people, but the cacophony and background activity actually helps me focus. A lot of that is probably due to my attention deficit of course, but I’ve been this way as long as I can remember. In college I loved going to the floor of the library that had the most chatter and group projects happening (as you went towards the basement the rule was be quiet). It just helps crowd out the noise and distractions in its own way.
Personally I don't think I'll ever get a desktop setup.