The big question for Apple is how many people are waiting for the iPhone X (AAPL)

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Two new iPhones went on sale this past weekend, but lines were not as long as they've been for previous iPhone launches. 

This has investors and analysts asking: Are Apple customers and fans passing on the iPhone 8 and waiting to see the $999 iPhone X? The iPhone X will be the most expensive and most technologically advanced iPhone when it hits stores on November 3. 

Bank of America Merrill Lynch analyst Wamsi Mohan said in a research note published on Monday that it was too early to say whether the iPhone 8 was a hit because the iPhone X isn't available yet. 

"Our availability tracker suggests that iPhone 7/7 Plus demand was slightly higher this time last year, but we attribute that to the staggered launch of the new iPhones where significant number of consumers are likely waiting to order the iPhone X (pre-orders start later on Oct 27th)," Mohan wrote. 

Citi analysts dropped their estimates for Apple's September quarter to reflect "more modest iPhone 8 and iPhone 8 Plus demand." 

Apple hasn't said anything about iPhone 8 sales yet, except for a quip by CEO Tim Cook that he "couldn't be happier" with the launch last Friday. 

"We've sold out of iPhone 8 and 8 Plus in some stores, but we've got good supply there," Cook said. 

Apple previously gave investors a big hint about how successful the new iPhone is by putting out a press release with selected statistics after an iPhone launch weekend. But Apple discontinued the practice last year, and has shown no sign of bringing it back. 

Apple issued strong guidance for the September quarter, which will end up containing a few weeks of iPhone 8 sales. But part of Apple's aggressive $49 to $52 billion revenue forecast may be that it raised prices on the iPhone 8 and iPhone 8 Plus over what the iPhone 7 series cost when it first went on sale. 

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The bottom line is that Apple is going to sell tens of millions of iPhones before the end of the year — it's just a question of what the mix of lower-cost and higher-cost iPhones is.

The combination of possible iPhone X shortages and seemingly weak demand for the iPhone 8 means that Apple might turn in a disappointing quarter or two before iPhone X supply catches up to iPhone X demand and pushes the sales "super cycle" some analysts have been hoping for.

And if demand for the iPhone 8 is soft, that just likely means that when Apple does start selling the iPhone X, there will be a lot of clamor for it. On Monday, KGI Securities analyst Ming-Chi Kuo estimated preorder demand for the iPhone X could top 40-50 million units, with tight supply until the first half of next year.