Idk. I agree with the idea put forth by some of the other posters in that the natural dog environment is amongst humans. To me it’s about the ‘jobs to be done’ fit that’s important for a dog. If they are naturally (for that individual) placed in an environment activity-wise that’s positive for the individual physically and mentally, then density doesn’t seem such a big issue. The hormone messing is a fair point, but behavioral change isn’t the whole picture on sterilization positives, as I expect some with veterinary backgrounds would attest to - simply the one which dog park goers might be most concerned about (in my experience, at least).
Where all this comes in to play for me is that in rural areas there’s a lot more room for activities and less probability to run into ill-fitting or unsocialized/untrained dogs - thus mitigating a lot of social risk.
I think of it as a handicap but city dog ownership is not unattainable, given reasonably modest resources and hard work. I’ve lived in and raised dogs in both urban and rural areas, fwiw