I'm generally in favor of blaming the consumer. Markets respond to pressures. If there were no market for dogs (especially pure-bred dogs), we wouldn't see so many breeders out there. I'm not giving the breeders any sort of free pass, but I've got to ultimately lay the blame at the foot of the consumer.
As for your own experiences, I can't speak to those. I've had good luck adopting from shelters even over a year. Old dogs can still learn new tricks. And when getting a young dog, there is no guarantee that you're not going to get one with any of various neuroses.
Either side (or both) could choose to stop the cycle.
I did not summon my dog into existence; had there been no dogs available directly from (reputable) breeders, I would have either found an agreeable candidate at a shelter, or not adopted at all.
As for your own experiences, I can't speak to those. I've had good luck adopting from shelters even over a year. Old dogs can still learn new tricks. And when getting a young dog, there is no guarantee that you're not going to get one with any of various neuroses.