In all the competitive battles that have defined the history of the technology revolution, one essential truth almost always determines the outcome: cheap and good enough beats awesome but expensive every time.

It happened when PCs beat out minicomputers (not to mention Macintosh’s). It happened when VHS killed Betamax. It happened when Linux pushed aside proprietary server operating systems. It’s happening now as Google’s Android overtakes Apple’s iOS.

Good Enough?

And it could be about to happen again with the Ubislate 7Ci tablet. This Android device is far from special in just about every respect. The specs are ordinary at best:

7-inch, 800 x 432 capacitive touchscreen

Android 4.04 Ice Cream Sandwich

1GHz Cortex A8 ARMv7 CPU

512MB RAM, 4GB storage

Wi-Fi (a version with GPRS cellular capability is also available)

VGA front-facing camera

Micro SD slot

Power, micro-USB, and headphone connectors

The speaker is tinny. The pictures are grainy and low-res, and the colors are off, too. The screen has to be held just so to be seen properly. Battery life is listed as a measly 3 hours, and in my tests the device couldn’t hold a charge more than a day or two no matter how little it was used. Performance is painfully slow for anyone spoiled by the latest tablets from Apple, Samsung, Microsoft and others. Things that should happen instantly take several seconds or more, and I experienced frequent hangups and glitches.

But build quality seems solid, and the thing is perfectly portable. Most important, though, it works – and it’s being sold for just $20 in India.

Like An iPhone 3GS?

Professor and entrepreneur Vivek Wadwha, who lent a test unit to ReadWrite for evaluation, compared the Ubislate Ci7 to an Apple iPhone 3GS, and in my tests that feels about right. If you can remember back a few years, you’ll recall that when 3GS first came out it felt plenty fast and revolutionary. And I think that’s exactly how the Ubislate Ci7would feel to someone getting ahold of their first tablet right now.

Sample Ubislate photo

But the iPhone 3GS was a hard-to-get, top-of-the-line machine when it debuted in 2009. For the Ubislate, Wadhwa says the Indian government has put in a bulk order for 100,000 devices at $40 each, which it then plans to sell to students in the countryside for $20 each. Wadhwa says they will also be available direct for $60.

It’s unclear how or when manufacturer Datawind will be able to deliver on this order, and when or if the tablet will make it to the U.S. and other markets. And it will no doubt cost a lot more on these shores due to testing, taxes and other issues.

Changing The Hardware Market

But even if the Ubislate never achieves mass distribution, in the U.S. or even in India, it’s still a game changer – for both hardware makers and Internet companies.

For the hardware market, iIt proves that a workable tablet can be created – if not yet delivered – at a price that makes it attainable to a lot more people than can afford even the cheapest mainstream tablets from Apple or Samsung and their direct competitors.

While people with means will always want the latest and best, the Ubislate is a step toward a world where almost everyone – Wadwha estimates that a billion people could end up with devices like this – has a tablet.

Maybe that tablet is not as good as the one on which you may be reading this article right now, but it’s more than good enough to give anyone access to this article – and to the rest of the Internet. And as history has shown over and over again, good enough and dirt cheap will swamp excellent and expensive every time.

Apple has made a lot of money selling tablets for $500 and up, and Microsoft is charging a whopping $900 or more for its upcoming Surface Pro. And I’m not saying those excellent products aren’t worth it.

But increasingly, those high-end machines could be competing against “good-enough” competitors that aren’t just 10% or 20% cheaper, but an order of magnitude cheaper. That puts a whole new kind of pressure of device makers to justify their high prices.

A Vast New Online Market – And New Competitors

Just as important, though, truly ubiquitous tablets will bring millions – perhaps billions – of new users to the Internet. These new Internet citizens won’t be as rich as the first billion people now online, but they will inevitably shift the center of Net away from developed nations.

That will open up vast new markets for Internet companies, if they’re clever and fast enough to come up with products and services that meet their needs.

But when the next billion people come online, they’re not just going to be consumers. We’ve already seen that as soon as people get access to the Net, they start figuring out how to leverage it to make life easier for themselves, and creating businesses to do the same for everyone else.

If truly cheap tablets really do double the worldwide Internet population, we’re sure to see a huge increase in online entrepreneurs. If you think there’s a lot of competition in the online app stores now, what do you think is going to happen when all those smart/ambitious/hungry new developers join the game?

If you don’t believe that changes everything, you’re just not paying attention.

For more, check out this video of Vivek Wadhwa presenting the $20 tablet at the inaugural ReadWrite Mix event in San Francisco: