I must admit that is a notion I don't understand. Why shouldn't it be possible to simply pay for a job and have it done by a professional? Like if I pay somebody to build me a house, am I supposed to give them ownership of the house afterwards?

If you build a house by having it done by a professional, you're going to be paying more to have it completed. There's usually contract clauses and insurance to ensure that you're not left with a half-finished house.

When you hire that professional, you're not only paying for his experience, but all those other things, as well. There's a premium attached to those clauses and insurance. You could choose to forgo those assurances, and save some money, but you have a higher risk. Not to mention, a lot of better professionals would refuse, thus limiting the pool of candidates.

The author of the article wants it all: the assurance of the higher-cost option without the premium.

Of course - if you give equity for workers, it is simply a form of salary. If they don't get equity, they should get a higher salary than workers who get equity. I agree to that. I just don't see why equity should always be a part of the compensation.

That's more of a startup oriented attitude. To continue the house analogy, if you wanted to avoid the premium associated with the higher contract, could enter into a similar agreement with the builder.

He builds the house on the cheap, in exchange for a percentage of the final selling price. If the contract was sound, why wouldn't that be an equitable deal?

There's probably a law against it, though (houses are funny that way).

In the case of the original post, I would be willing to work there - as a very expensive contractor, with the degree of my loyalty explicit in the terms. He'd probably object to the part about him paying my attorney to review it, though.

It's not, or didn't use to be, all that unusual in houses. It's referred to as building "on spec", meaning "speculative"; where the architect, builder, or whoever builds the house on the chance that they can make a profit selling it after, rather than the more common way of building it to an up-front contract. It was most often used when a builder had materials or a little cash available to avoid laying off good workers when there wasn't a contract job available.