Why Don't people train their dogs

I'm wondering why the hell people don't train their dog. Or even if they can afford it hire a personal trainer and just leave them to train the dog for them.

I work as a dog walker and unfortunately I cannot opt out of this because these dogs don't have any walkers to go to, I am with three reactive dogs to not only are not really fans of other dogs but can become reactive out of the blue or one another dog is being reactive.

Even worse is these dogs are not least trained which makes it so much worse because it means that they don't understand that they can't just walk anywhere.

One is constantly overstimulated and did not want to walk and the other two wanted so badly to walk that they wouldn't follow the direction of whoever was walking them. They were also on no pull harnesses which did not work because they would keep pulling regardless or even worse is they would pull backwards for the one who was overstimulated.

I had to plead for weeks on end to my boss to allow me to get gear that would allow them to walk properly because there's nothing me or the owner can do about it. I mean there's a ton of things to owner can do about it but if they wanted to do that they would have done so already.

I get them all gentle leaders and they're immediately walking without me having to put any pressure on the leash to get them where they want to go. They don't like it but unfortunately in order for me to not quit my job this is what has to be done.

My boss at first acted like I was insane because he thought that I was the only one experiencing this problem one before they were never in a group where they had to walk for 3 hours straight. And then later on he tells me that he always had difficulties walking these dogs?

I don't own a dog but I can see it's kind of stuff from a mile away. So why do people feel so okay with not training their dogs? It's dangerous for the dogs for other dogs and for other people and the handlers.