I've noticed this in parts of the UK as well. My parents wanted a dog, and when they compared how many were in a reasonable distance with how many there were in a similar distance to the area of the US my dad often has to travel for work it was opposite ends of the spectrum. There were hardly any near us, but pages and pages of suitable dogs in the US.
They tried to get one anyway and the main things they wanted in a dog were one that would be active enough to go places with them, because they're both active people, and one that was fine with other dogs because they live in an area where a lot of people have dogs and let them off leads. It didn't have to be the most sociable dog in the world, just not aggressive or terrified of other dogs.
The first shelter left out vital information about the dog they were interested in on their website which meant she was unsuitable. They suggested another dog based on their needs and my parents took this dog on two walks and fell in love, decided to put the deposit on him to take him after they finished the unnecessary third walk before adopting him, when he showed a ridiculous amount of aggression toward another dog. He was a big dog, and my mum wasn't strong enough to control him when it happened. The shelters response "Oh, well, yeah. Hadn't we mentioned that?" They hadn't. They didn't have any more dogs that were comfortable with other dogs. So my parents decided to look at a different shelter closer to home.
Again, upon visiting, the dog they'd been interested in on the website had vital information left out and they were told she wouldn't be suitable when they asked about her and were recommended another dog. The only dog that fitted "okay with other dogs, active" and it turned out to be the one breed they didn't want - a chihuahua. They gave him a chance, and went to ask the shelter's adoption advice woman more about him and she said he was probably better for an experienced chihuahua owner anyway, because he had a few chihuahua specific issues. So that was another shelter ruled out after basically being told they didn't have a single dog in their small number of dogs that was active and comfortable around other dogs.
So they tried another shelter. This one required a home check before you could even meet the dogs, but there was a cockapoo puppy my mum had fallen in love with so she had the home check done, and three days later got an email "CONGRATULATIONS you passed your home check. But we are afraid you were unsuccessful for the puppy, we'll get in contact if another suitable dog comes up." They emailed again a couple of days later with a lovely elderly dog who wanted a quiet home because he wasn't active, and no other available dogs on the website. And that was all the shelters in a reasonable distance covered and they were completely disheartened.
They ended up buying a puppy from a lovely family whose farm dogs (as in rural working farm, not puppy farm. The dad dog was their sheepdog) had a small litter. They got to visit the farm, meet both the dog parents and the family, see the puppy playing with her brothers and parents and the family wouldn't let her go until she was old enough to have had both sets of vaccinations she needed and vet, worming and flea checks. Sometimes people can have great intentions, but it can just not work for them.