At 50 properties, your friend probably could start leveraging a team and either get more properties and more income or simply get more time for himself and still have enough income. But, a lot of people will have topped out at 10 or so properties, if you're paying other people to do the work there, you may not be making enough income to grow your assets.
My personal pet-peeve: In 99.9% of cases, when people talk about "leading" in the business context, what they really mean is just "managing". Let's not infest our language with corporate newspeak.
Edit: I’ve just realised that your 4th example was Jesus, and you weren’t started with a curse - I’ll leave my error as I like it.
I generally agree, but I have never ever seen that in a business world. What the business owner wants - maximum profit - is in a direct conflict with employee wants (maximum salary for an easy and/or fullfilling job), so I can't see them ever wanting the same thing.
In general, people are willing to forgo their immediate interest (high pay, interesting tasks) only if they believe they're doing something for a greater good, and that does not happen in companies. Even if you're crunching on some innovative product that will make the world better (which is the claim that is often used to motivate people in startups), the main reason for the crunch is that you're trying to beat X other companies that are also working on the same innovation. So, even in such case, you're mostly killing yourself to make the owners rich, as the world will be a better place regardless of whether it's your company or your competitor that manages to win the race to the market.
The other part is being a good coach, which is not about giving advice, it's about helping someone take responsibility for their tasks and helping them learn how to improve.
That's just my opinion, and I'm not a manager so maybe I have no idea what I'm talking about.
I have done it both ways...
Concrete trucks are about $80-120 / yd. mixing bags of concrete, assuming you have free aggregate and sand, is about $200 / yd
He does as much work as possible himself, or when I was living at home, by getting me to do it for free (well, I get inheritance one day).
The amount of money he's managed to save by doing his own work is staggering. We saved at least $10,000 by building a retaining wall ourselves. We mixed up over 6 tonnes of concrete in a 200 L concrete mixer.
Every fence on his properties he's put up himself, I've helped out with about 5. You're probably saving $5000 per fence (for a timber fence, 6 foot high). He does a lot of his own painting and drywall work as well. He does a lot of his own electrical work as well since he's qualified to do it, which saves boatloads of money.
We even installed the pool at the family house on our own, saving 5 figures (he did pay for a earthmoving company to dig the hole though).
He's probably managed to save several hundred thousand dollars by doing his own work. He basically spends any time that he's not working at his day job working on his properties.
Building your own house from scratch isn't really worth it these days though. It's cheaper to get a frame preassembled, then trucked in and erected. Doing your own concreting isn't really worth it either, same for bricklaying.