The higher payout was previously only available in the US, Canada, and western Europe. While Amazon did tack on pricing restrictions, they had not previously tried to block you from selling your ebook elsewhere. With today's move we can now see Amazon extracting an extra bonus for themselves from the money they pay to authors. This is something that I had been half expecting to see for some time now, and in fact I had thought Amazon had already done so.
Now I think we see why the 70% royalty option was limited to a handful of ebook markets; Amazon was holding out for a way to insert this exclusivity requirement. They've always wanted to be the only ebookstore, and this could be how they do it. How much do you want to bet that when Amazon launches the Brazilian and Japanese Kindle Stores they also expand the 70% royalty options with the same requirements as in India?
Actually, the better option might be announced shortly after the new ebookstores open. Amazon launched the local Kindle Store in India in late August, but only expanded the royalty option today, a month later.
image by archer10 (Dennis)