I don't think it has to be so extreme. I have "show" friends, "sport" friends, and friends that just have pets, some of them keep all their dogs, some of them rehome them after they are retired from show, or rehome a dog that isn't going to "make the cut" in show or sport....rehoming a retired dog or a dog that isn't cutting it isn't bad at all in my eyes...they aren't doing it with fire in their eyes, cursing the day the dog was born...they are just in a business or sport...can't/won't keep over a certain amount of dogs, and if they kept every single one they tried to show/use in sport until the day it died (we're talking a decade or more per dog)...they may not be able to get super far because they only want 2 or 3 dogs at a time...NOT a big deal to me...now, if they are euthanizing an animal or going through dog after dog after dog...that's something completely different. But, rehoming a dog isn't horrible....and I understand it in a lot of situations. I don't think it has to be as dramatic as you are making it, nor do I think they are as flippant about it as you are making it seem....and I don't think most of the shelters are full of sport/show dogs that didn't make the cut...there is a completely different "culture" or group of people that are the cause of that.
Yes, there is a value for my dog. I actually agree with Blitz...it's pretty high, because I love him to pieces, but if I knew he was going to a good home, and someone offered to pay for my child's college to take him....I'd consider that lol....still haven't gotten that "one in a million" dog yet...but I also don't get super duper emotionally attached to my dogs...I think I just know too much about biology/animal behavior/genetics/the reason they mentally do what they do....and I know I can be easily replaced to them with someone else who feeds and cares for them.
I also have a child...and the love I have for my child is just incomparable to that for my dog...BUT, I had a dog before my child...and it made me sick to imagine life without the dog, the dog filled the place of "child" in my heart...that's why my heart completely understands people who don't have children saying their dog is like their child...I believe it is whole heartedly...
After a child, everything else (to me) was second in love to him....if that makes sense lol....I am not trying to say I don't love my dogs..but it is not...will not...ever be comparable to that of my son.
Edit: Just wanted to add...I am NOT saying people need to love or feel about their dogs the same way I do...I just think it's ridiculous to say, "I never understand how people could give away a dog if it isn't working out for them..." show, sport...etc...and judge those who do as thoughtless or wrong....most people I know who gave up a potential sport dog or show dog were pain-stackingly thorough in finding a home for it, and always checked up on how it was doing....they didn't just throw it to the pound(I've worked in lots of shelters....VERY rarely did we get show/sport dogs from owners that said they couldn't make the cut...I cannot think of a single example....I also don't think it's wrong for people to look at their pets as pieces of property that they feed/care for....as long as no abuse (starving/beating/leaving exposed to dangerous elements etc) is happening, whatever.