You're seeing things as if there are only two types of people, the motivated ones who get a 120kg squat in a few weeks, and the lazy unmotivated ones who never squat at all. At the very least there's a third type, the person who will do great things if they get some encouragement and instruction.
Your third type will do alright, but I've never heard of a Great in any field who's not super motivated all by him/herself. Please reserve the words "great things" to people who actually accomplish them.
I actually consider myself lazy. I don't train all that hard, compared to many PTC lifters or some people I've seen at my club.
You're doing well with your clients, and getting them to train right. That's a good thing. However, what you described of them is nothing but weak attitude. They require you to nurture and hold their hands through out and stupidly get intimidated by stronger people who have trained for much longer. And that's why you are their personal trainer and not their coach. That's fine, but call a spade a spade. People who can't bear the thought of themselves being weak are indeed weak, because they can't stand up to their own ego and can't control their insecurities.
Maybe one day those people you're training will have a strong attitude, but right now they're weak and need to get stronger. Nobody's born strong (except Hercules and Paul Anderson).
You have your work cut out for you, because those people are products of the decades-long self-esteem movement where they need an abundance of positive encouragement for the tiniest bit of achievement they manage, and any compliment less than the level of "you're awesome, you're beautiful, you're amazing, you're great etc." is an insult.
I'm just glad I don't have to do what you do.
Of course I don't talk like this to those people, but I think the ones who go seek out information on forums like this, like Muu, are already self-motivated enough and don't need the faux pats on the back. I believe they'd appreciate the more candid talks.