Customers queue to buy Apple's new iPhone 5c and 5s at the Wangfujing flagship store on September 20, 2013 in Beijing, China. China Mobile, the world's largest mobile carrier, will begin selling iPhones in January. - 

Apple received an early Christmas gift this year: 760 million potential consumers. That's how many Chinese people subscribe to China Mobile, the world's largest cell phone carrier. Last night, Apple and China Mobile signed a long-awaited deal to sell iPhones to this pool of nearly a billion new customers.

"China Mobile by itself is more than seven times larger than the biggest US carrier – AT&T or Verizon," says Philip Elmer-Dewitt, a journalist for Fortune who's been writing about Apple since 1982. "So this is just a huge get for Apple, and I’m sure Steve Jobs would’ve loved to have had it before he died."

But the big question is how many of those 760 million people who will soon be eligible to buy iPhones will actually buy them? China Mobile will roll out the iPhone on its new 4G network, and only a fifth of China Mobile subscribers actually use the current 3G network. While that's still a lot of people, it's also an indication that there might not be as many customers in China Mobile's vast network who are willing to pay for faster service.

"Frankly, the China Mobile 3G network has been heavily criticized by users for being slow because they use a homegrown system," says Shaun Rein of the China Market Research Group. "So I expect this to boost sales for Apple -- but not as much as people think in the short term -- because a lot of consumers are going to take a wait and see attitude about whether or not 4G is good."

Rein predicts that Apple may sell 10 million iPhones -- a fraction of what they would have sold had they done this deal few years ago, before the Chinese market was saturated with competing smart phones.

So what took so long to get the iPhone on China Mobile? The two companies both think very highly of themselves, and they're used to getting what they want.  Apple didn’t want to modify the iPhone to conform to China Mobile’s nonstandard wireless protocol, and China Mobile didn’t want to budge.

Apple does have impeccable timing, though.  China Mobile subscribers will be able to buy their new iPhones in mid-January.  Just in time for Chinese New Year.

Follow Rob Schmitz at @rob_schmitz