1st- I'm not taking sides here....
I can fully imagine training without treats. You have to understand what motivates your dog and use that. My GSD Gunnar could care less for treats while training, and while he'll take them, it takes him literally 30 seconds to eat a pea sized tidbit, which breaks our momentum. For him it's all about a toy reward, and we can do several tasks and then reward at the end of those tasks with some tug or ball play. He will go nuts when I show him his tug, and his commands are done with speed and enthusiasm, much more when I show him a cookie. I use a prong collar on him. The only time he's corrected with it is when he refuses to do a command that we have proofed- meaning, he's been taught the command and he has been exposed to increasing distraction and still performs the task as requested. Prime example- on the protection field, he's in high drive, he wants the decoy bad. He's put in a down/stay. If he makes a motion toward the decoy, he gets corrected. Most of the time it's a verbal, because it's faster for me to react that way, and 99% of the time he'll drop back down again. His leash is hooked to his harness, with a small traffic tab hooked to the prong. The only way he'd get a prong correction would be if he ignored the verbal, and engaged the decoy, he'd be pronged off of the decoy. Once he was taken back and put in a down, and he listened, then he'd be rewarded with a bite.
Daisy is 100% food motivated, so we use treats for teaching her new tasks. She's also toy motivated, and I can slip obedience in when she's playing fetch- things like long downs while I toss her ball away as a distraction, and then release her to go get it, stuff like that.
I think everyone's ultimate goal is to phase out whatever motivators you need. I also think that doing certain tasks, like running the agility course or things like that, I will always give a toy reward for.