Just to say while I have tried to support rescues, DH and I decided recently that we wouldnt have another cat rather than go rescue again.
We and various family members have had lots of rescues over the last 20 years. We are finding: the only kittens they seem to get are the offspring of feral cats. Even when taken as 12 week kittens & worked with extensively, they become poorly socialised fearful cats which frankly speaking make crap family pets as they avoid most people and all children.
The older cats in rescues where we live are often similar. Relatively fearful, almost semi feral cats or one with chronic health conditions or other poor behaviours. Rescues often refuse to let people with young children have a pet.
By contrast, we also adopted a kitten, given away for free by a friend who's lovely family cat had an unplanned litter. We got her at 9 weeks, she is extremely social, loves our children and is happy to be stroked and fussed over by them and visitors, neighbouring children etc. Neighbour who bought a kitten from a breeder at similar age has had similar experience.
Rescue vs buying cats are different things. Rescues are driven by animal protection and welfare and whether unconsciously or not, don't really care if an animal will be a suitable pet for the family, as long as the animal's needs are met. It's not very sustainable as most people just want a friendly pet tbh.