I have never used treats in my training. Not sure why but thought that I was the centre of attention rather than food so made sense to meLots of people think of dogs in terms of the lassie concept - that they shouldn't need rewards because we should just be the centre of their world regardless and they will do our bidding for us

. Dogs don't really work that way - they do something because it's rewarding and if something isn't rewarding it is much less likely to happen again. If you have dogs that just enjoy working and going out for walks and having human contact then that is great and you are still rewarding them with these things and that is what makes you the centre of their world not just because it's 'you' so no different than if your dog is not so motivated by those things and you use food as a reward, there is something that makes you interesting to them.
My guys are also incredibly focussed on me, but it is because I use the rewards they love and like theemx says I use what is rewarding to each individual dog to make life easier for myself - so for one, she thinks I'm fab because she gets to chase stuff, which is her biggest reward and that always happens through me, plus her second motivator is food and I am the one who feeds her, normal food and treats. For another I am worth listening to because she gets to play tuggy with me or having something really high value to eat as a reward. For another, she doesn't really have a favourite she just likes lots of things and gets bored easily so for her, meeting other dogs, chasing a ball, having goodies, going for a really good sniff area all used as rewards because any one thing would bore her and would lose it's value if over used.
Collies for example often don't need mush outside reinforcers for working because they just love to be working and will rpeat behaviours over and over just for the hell of it - it's not just about doing it for the person though it's because they find working with people and working generally rewarding so looks like they are just doing it for the love of their person.
One things I will put extra effort into making rewarding is food because it can be so useful for training, particularly if you have a fear aggressive dog and are trying to desensitise them as it is so useful in terms of repititions and timing of the reward but there are plenty of wys of being rewarding to your dog without using food. I also find it easy to swap rewards from one thing to another for dogs and also find the reward very dependant on the situation, so often for the initial teaching will use food but then when I want more speed for example will use a more adrenaline fueled reward such as chasing something.