For all you out there looking to “completely change the game,” take heed. Sometimes it’s easier to win the game you’re in.

I have a hunch that has yet to be borne out completely in the real world of results, but hear me out anyway. I think that the explosion of e-readers has changed the book industry completely and for the better. I also think that it has flattened the playing field.

And this might just be bad news for Amazon, the guy with 90% share in the room.

Amazon wowed us with recommendations from others like us, turning us on to titles and authors we’d never heard of but that others who had bought this exact book had. As a result, we bought more books of a varied nature and enjoyed them. Amazon began to learn us. Their recommendations just got better and better. Soon, Amazon was the only name in books (and other things, but let’s stick to books for now).

Then, they launch the nuclear game-ender. The Kindle. They can now put a book in your hands in seconds, the only Achilles’ Heel that an etailer has to contend with versus brick and mortar.

As Ray Kroc is attributed to have said, “When your competitor is drowning, stick a hose in his mouth.” So they did.

And Amazon’s primary competitor, Barnes and Noble, was drowning. B&N’s Nook came late to the party and was little more than an expensive Kindle on the other bookseller’s platform.

Then, something interesting happened. Two things, really. First, the Nook was hacked to make it a moderately functioning tablet computer. More importantly, B&N embraced this change and soon launched an OS that not only allowed this hack to continue but pushed hard into this space. Second, it launched a better product: a touch-screen color Nook.

Have you played with a Nook next to a Kindle? The Nook is just better.

It’s got a touch screen. Do you own a mobile phone today?  If you do, it’s probably a touch screen device. Our frame of reference has shifted to touch screens on handheld devices, hasn’t it? It’s color, like most of our handheld devices are. It makes more sense. The Kindle, which cheaper by $100, is still a very attractive product that, because of the comparison with the Nook, is something we can live with – but it’s not the one we want. The first time I picked a Kindle up, I kept poking the screen expecting it to do something.

But apart from the speeds and feeds of one versus the other, what really happened? Amazon, which won us over with its recommendations and reviews and its superior user experience on the web, turned the game into an e-reader contest.

The books all look the same once you’ve bought them. Same words on either device. Same price, too.

So if you like the B&N device better, why wouldn’t you just buy the device you want and then start buying all your books from the new commoditized “content farm”?  You still get your books instantly either way.

Amazon, in short, changed the game and instead of killing off its competitor, it allowed it to be reborn and to compete on equal – or superior – footing.

It’s no longer about the recommendations and the feeling that Amazon knows me anymore. It’s about a device. An e-reader. Hardware. The playing field is now flat, where once it was decidedly stacked in Amazon’s favor.

Does this mean Amazon’s in trouble? I don’t know. Plenty of things can still fell B&N. Amazon is rumored to be launching a color tablet aiming at the iPad and is already taking active steps to do to publishers what it did to brick and mortar bookstores. It’s a pretty tough competitor to have to face, in other words, and it’s not making a lot of mistakes. My money is still on Amazon to do just fine.

But it does give us a cautionary tale worth considering.

When a market leader decides to change the game into “game over” mode, they’d better make sure the new game gives them more of an advantage than the old one did.