Let's pretend I've decided to build a spice rack.
I've done small woodworking projects before, and I think I have a pretty good idea of what I need: some wood and a few basic tools: a tape measure, a saw, a level, and a hammer.
If I were going to build a whole house, rather than just a spice rack, I'd still need a tape measure, a saw, a level, and a hammer (among other things).
So I go to the hardware store to buy the tools, and I ask the sales clerk where I can find a hammer.
"A hammer?" he asks. "Nobody really buys hammers anymore. They're kind of old fashioned."
Surprised at this development, I ask him why.
"Well, the problem with hammers is that there are so many different kinds. Sledge hammers, claw hammers, ball-peen hammers. What if you bought one kind of hammer and then realized that you needed a different kind of hammer later? You'd have to buy a separate hammer for your next task. As it turns out, most people really want a single hammer that can handle all of the different kinds of hammering tasks you might encounter in your life."
"Hmmmmmm. Well, I suppose that sounds all right. Can you show me where to find a Universal Hammer."
"No, we don't sell those anymore. They're pretty obsolete."
"Really? I thought you just said that the Universal Hammer was the wave of the future."
"As it turns out, if you make only one kind of hammer, capable of performing all the same tasks as all those different kinds of hammers, then it isn't very good at any of them. Driving a nail with a sledgehammer isn't very effective. And, if you want to kill someone, there's really no substitute for a ball-peen hammer."
"That's true. So, if nobody buys Universal Hammers anymore, and if you're no longer selling all those old-fashioned kinds of hammers, what kinds of hammers do you sell?"
"Actually, we don't sell hammers at all."
"According to our research, what people really needed wasn't a Universal Hammer after all. It's always better to have the right kind of hammer for the job. So, we started selling hammer factories, capable of producing whatever kind of hammers you might be interested in using. All you need to do is staff the hammer factory with workers, activate the machinery, buy the raw materials, pay the utility bills, and PRESTO...you'll have exactly the kind of hammer you need in no time flat."
"But I don't really want to buy a hammer factory..."
"That's good. Because we don't sell them anymore."
"But I thought you just said..."
"We discovered that most people don't actually need an entire hammer factory. Some people, for example, will never need a ball-peen hammer. (Maybe they've never had to kill someone. Or maybe they killed them with icepicks instead.) So there's no point in someone buying a hammer factory that can produce every kind of hammer under the sun."
"Yeah, that makes a lot of sense."
"So, instead, we started selling schematic diagrams for hammer factories, enabling our clients to build their own hammer factories, custom engineered to manufacture only the kinds of hammers that they would actually need."
"Let me guess. You don't sell those anymore."
"Nope. Sure don't. As it turns out, people don't want to build an entire factory just to manufacture a couple of hammers. Leave the factory-building up to the factory-building experts, that's what I always say!!"
"And I would agree with you there."
"Yup. So we stopped selling those schematics and started selling hammer-factory-building factories. Each hammer factory factory is built for you by the top experts in the hammer factory factory business, so you don't need to worry about all the details that go into building a factory. Yet you still get all the benefits of having your own customized hammer factory, churning out your own customized hammers, according to your own specific hammer designs."
"Well, that doesn't really..."
"I know what you're going to say!! ...and we don't sell those anymore either. For some reason, not many people were buying the hammer factory factories, so we came up with a new solution to address the problem."
"When we stepped back and looked at the global tool infrastructure, we determined that people were frustrated with having to manage and operate a hammer factory factory, as well as the hammer factory that it produced. That kind of overhead can get pretty cumbersome when you deal with the likely scenario of also operating a tape measure factory factory, a saw factory factory, and a level factory factory, not to mention a lumber manufacturing conglomerate holding company. When we really looked at the situation, we determined that that's just too complex for someone who really just wants to build a spice rack."
"Yeah, no kidding."
"So this week, we're introducing a general-purpose tool-building factory factory factory, so that all of your different tool factory factories can be produced by a single, unified factory. The factory factory factory will produce only the tool factory factories that you actually need, and each of those factory factories will produce a single factory based on your custom tool specifications. The final set of tools that emerge from this process will be the ideal tools for your particular project. You'll have exactly the hammer you need, and exactly the right tape measure for your task, all at the press of a button (though you may also have to deploy a few configuration files to make it all work according to your expectations)."
"So you don't have any hammers? None at all?"
"No. If you really want a high-quality, industrially engineered spice rack, you desperately need something more advanced than a simple hammer from a rinky-dink hardware store."
"And this is the way everyone is doing it now? Everyone is using a general-purpose tool-building factory factory factory now, whenever they need a hammer?"
"Well all right. I guess that's what I'll have to do. If this is the way things are done now, I guess I'd better learn how to do it."
"Good for you!!"
"This thing comes with documentation, right?"