I'd argue that venues like this are comfy because they are so dead. Post quality was relatively high from the beginning, with it moving so slowly users don't check constantly which throws away the "urgency" to respond and allows for well crafted answers. At the same time, new users are rare because this place is somewhat hard to find and they see that they need to commit time since as previously said answers take time to come. This makes it so only those really interested will participate, and they will follow the established non-rules of high post quality.
If this place had been more popular, answers would come quicker and new users would interact as their interaction would bring immediate result. They would also keep coming for instant gratification, initial user base would be invaded and post quality would lower as "trolling" would become a possibility and "hot" reactions to other posts happen.
Sadly, the masses ruin everything, and so it is both a blessing and a curse that comfy places forever shall be dead.