Requirements regarding spay/neutering - how do you enforce that? Most free-roaming cats (pets or not) are not, in my experience.
As far as male cats who are neutered not having that “special” smell. It might not be as potent, but cat pee is still EXTREMELY irritating to my nose. If I am around it much, it makes my ill.
And I firmly believe that you are in the minority regarding cat ownership. I know quite a few cat owners. I would say less than 2 out of 10 take their cats to the vet. The percentage goes up for full-time house cats.
There are some pretty big fines for letting your pet roam freely here where we live. Not many dogs running free (in fact, haven’t seen any in the 16 months we have been here). But lots of cats.
Still - personally, I just can’t grasp allowing a pet to roam freely outside. Dogs - letting them out into a fenced yard or run for extended times - sure. But cats don’t respect fences (or property lines - or, apparently, wood piles that belong to others).
The cat I grew up with went to the vet for more or less annual rabies shots. This cat was allowed the outdoors and she lived about thirteen years (my dad accidentally backed the car over her, and she didn’t hear it because she was deaf). Now all my kittehs stay inside. Too many cruel people out there.
At least where I live, the requirement is that they wear a current rabies tag any time they're outside. The rabies tag is traceable to the vet who did the vaccination, who will also have a record of the owner's identity and the cat's spay/neuter status. If anyone complains about a stray cat, and animal control finds it's untagged, it's going to get carted off to the shelter. If it's micro-chipped, or if the owner realizes the cat is missing and picks it up at the shelter before its 3 day hold it up, the cat will get home, but the owner will be paying a fine that costs more than a spay/neuter *and* they won't get the cat back until it's spayed or neutered at their own expense. There are some cats roaming around my neighborhood without tags, but not many, and they're probably strays. At least half of the cats I've encountered helping themselves to the bowl of cat food I keep on the porch, have had tags (rabies and also cat's name/owner's phone number). I'm not the only person on my block who carts unfixed cats off to the vet for a fixing and rabies shot -- fortunately my neighborhood has enough people who care and can spare the money, that the cat situation has never gotten out of control. More than one cat "owner" on my block has unexpectedly discovered that Fluffy lost part of his/her anatomy while away from home. I don't ask permission even if I know who the "owner" is -- it's illegal for the cat to be outside if it's not fixed.
Mine generally don't go far, though I had one some years back who was a roamer. He was quite a character and had lots of people friends all over the neighborhood. I met quite a few neighbors though that cat, when they called the number on his tag to make sure he wasn't lost. It depends where you live of course -- if I was in an area with foxes or coyotes, or right next to a big highway, I'd build them a big outdoor enclosure and not let them run free. But in an ordinary suburban neighborhood, it's really not hard to keep them close to home. The cat door is always open, so they're not locked out and roaming around looking for food or shelter. There's a little fake pond with a fountain in backyard, replaced with a heated water bowl in winter, so there are always lot of birds and other wildife for entertainment. Plus we throw bird seed in the driveway every day, so it's like non-stop kitty TV (if any of my cats show a propensity to catch birds, they promptly get a nice loud bell attached to their collar, which puts a stop to catching any birds that nature intended to survive and reproduce). And a couple of years ago, we added a little bed of catnip near the back door and cat door. With the exception of the one now-departed roamer, my cats don't go any farther than immediately adjacent properties. Since they always have a tag with my phone number, if they were bothering anybody, the person would call me. But in 20 years living in the same house, I've never gotten a call complaining about any of my cats -- just lots of calls checking to make sure the cat isn't lost (especially from the roamer, who was *really* good at doing the poor lonesome lost kitty act to get the non-stop attention he craved).