As I was reading Ashlee Vance’s “Elon Musk: Tesla, Space X and the Quest for a Fantastic Future,” I was alternately awed and disheartened, almost exactly the same ambivalence I felt after reading Walter Isaacson’s “Steve Jobs” and Brad Stone’s “The Everything Store: Jeff Bezos and the Age of Amazon.”

The three leaders are arguably the most extraordinary business visionaries of our times. Each of them has introduced unique products that changed – or in Mr. Musk’s case, have huge potential to change – the way we live.

I was awed by the innovative, courageous, persistent and creative ways all three built their businesses. I also love their products. I own a Mac Pro and an iPhone, and I have been a loyal customer of Apple for 20 years. I buy many books and other products on Amazon, lured by a blend of low prices, ease of purchase and reliably quick delivery. The Tesla Model S is hands down the best car I have ever driven, and it’s all electric, rechargeable in your garage.

Plainly, I have bought in to what these guys are selling.

What disheartens me is how little care and appreciation any of them give (or in Mr. Jobs’s case, gave) to hard-working and loyal employees, and how unnecessarily cruel and demeaning they could be to the people who helped make their dreams come true.