Oh you appear to be under a misapprehension, it doesn't take 2 months to do the paperwork. It takes about 15 minutes, but you have to wait for a cooling off period and then for processing which depends on the current admin load. So it's very quick in terms of effort, it takes you an afternoon including the training course and then it's just a matter of waiting with no more effort required.

To address your questions, for my mortgage it took us about 3 months to get everything together, not including the saving for a deposit. We needed to get a conveyancer, find the house obviously, get preapproval which involved getting lots of information about our finances and stuff together and applying to multiple banks to compare offers, then we paid a deposit, got a building inspection, needed to get insurance which was another few days of shopping around a phone calls, then we had to wait while a bunch of legal shit was done and the contract to settle which was 2 months. So yes! a lot more involved and expensive than when my wife got her licence which as mentioned only took an afternoon's effort.

Getting fit is relevant because it's an example of something people do which requires way more effort; it requires multiple days per week for months! yet more people are fit than own guns.

Child same deal as fit but more paperwork. My sister just had kids and aside from the pregnancy which was obviously rather intense they had to move, negotiate time off with work, apply for various benefits from the government, multiple screenings etc and vaccinations. She was busy as hell and she's committed to being busy as hell for like 10 more years. Heaps more effort than a firearms licence, and again very common.

Travel vaccines is a multiple week program (you can't get them all at once) and each visit to the doctor is 100 dollars or so. Plus wait times, travel like owning a firearm is often a luxury hobby so I think they're comparable. Defs harder to travel than get a gun, yet again most people do it here at some point.

You can call all of NSW lunatics if you like, but motorcycle licensing is usually done by people who already own a car and are doing it for a hobby. I did it and found it easy, at the training most conversation was about how easy it was and how excited we were to ride. When I talk to people who don't ride they have never mentioned the licensing as a barrier but instead it is almost always fear of injuries (quite reasonable) or lack of desire.

You can invent your own standards for what counts as onerous licensing, and if you're in the USA I can see why the aussie system would look very difficult. I only mean to show that it isn't considered difficult here, and provide common examples of things people do that involve way more paperwork, cost, and/or time. It's also worth nothing that some states in australia have much more lax licensing requirements for firearms without much higher ownership. It is a lack of desire which stops people, a minor barrier is enough to stop people who are just mad at someone and wanting to shoot them from doing that. People that premeditate crime aren't stopped, and yet no shootings problem.