Bitcoin is an amazing technology. I admire it. The central idea of how to implement a virtual currency with no one in charge, but where the “bank vault” is nonetheless pretty safe, is clever, as I explained here. However, the second you take this clever idea and apply it to situations for which it was not designed, it quickly becomes ridiculous – inferior by factors of thousands compared to existing solutions. It’s as though you liked hiking and camping in a tent — and went back to your home on your suburban block, knocked your house down, disconnected from electricity, municipal water and sewer, stopped garbage collection, sold your car and bicycle, and gloried in your new, improved way of living during cold winter nights. Good idea, but wrong place, and there’s probably a reason few people choose to live that way.
As a start for understanding why private blockchain is a ridiculous notion, let’s imagine that we all live in buildings with municipal water supply, and that suddenly someone decided it would be cool to live “off the grid” in a dry area where it does rain, but infrequently. How are you going to get and store the water you need to live? Obviously, you have to somehow make maximum use of the rare rainfall that happens. You construct as wide and varied a system of rain-catchers as you can. If you have a house with a roof, you arrange the gutters to go to downspouts to rain barrels. You carefully construct the rain barrels so they don’t leak, since water is precious, after all – the rain barrels have to be “immutable.” You also stretch out any canvas or anything else you can scrounge up to capture the rain before it hits the ground, and route it to barrels. You construct a set of pipes to connect the barrels, to make sure that all the barrels have water, and none has too much. You end up with a distributed set of barrels, each containing the precious water you need to collect and preserve. The system is even more impressive when it supplies a small encampment of people, with pipes distributing the water among the barrels, assuring that everyone has enough water.
Anyone wandering in the wilderness who encountered this maze of connected, distributed, immutable barrels and rain catchers would be impressed at what a good solution it was to the problem of having enough water when there’s no municipal water supply. Someone might come out to the place, take lots of pictures and blog about it. It might catch on, and some homeowners with regular water supply might be attracted to the notion of being ready to survive when civilization collapses and everyone will be forced to live off the grid. Most people, of course, will be happy to continue enjoying normal hot and cold running water, available by turning the faucet.
The Bitcoin solution was specifically designed when you really don’t want a municipal currency authority. Like the distributed water catchers and barrels, it’s a clever solution for exactly that problem. What happens when you decide it’s OK after all to have someone in charge – you’re not in the desert, you’re not a survivalist, and you just want a convenient water supply? What kind of sense does it make to somehow get a private corporation to be completely in charge of the system of water catchers, pipes and barrels in a place where connection to central water is readily available? Do you think the new system would be less expensive, more convenient and less obtrusive? Do you think the privately run immutable distributed water system, with all its barrels, catchers and pipes would be able to handle sudden demands like filling your pool or even a few houses running their lawn sprinkling systems at the same time?
That’s exactly what’s happening with private blockchain implementations. Every single vendor that so enthusiastically promotes its private blockchain tells you quietly what’s wrong, things like the transaction rate is worse by factors of thousands compared to normal DBMS’s (of course they don’t put it that way), and a host of other deficiencies that they’re overcoming … by step-by-step adapting standard database techniques first deployed decades ago and by now standard methods, and making an “improved” private blockchain. Improved, but still dramatically worse by all measures compared to standard technology.
Blockchain is a pile of new software that was designed to solve a very special problem that does not occur in normal life. Private blockchain is an attempt to take that highly unique solution, designed for wilderness living with no central authority in charge, and apply it to normal urban/suburban life with a central authority. The amazing, cool and different things about blockchain were invented specifically to solve the problem of having no central authority. The second you introduce a central authority, i.e., make it a private blockchain, all those special things that make blockchain unique suddenly become huge impediments, obstacles with no redeeming virtues. It makes as much sense as camping out in your suburban back yard — OK if you’re a kid or want to give your tent a dry run, but nothing any sane person would think is an improved way of living.