During its product launch keynote in September, Apple (NASDAQ:AAPL) announced three new iPhone models: iPhone 8, iPhone 8 Plus, and iPhone X. The iPhone 8 and iPhone 8 Plus became available for purchase shortly after the announcement, while the availability of the iPhone X was delayed until Nov. 2. 

There was some expectation -- from both analysts and key Apple suppliers -- that because of this staggered launch, Apple's iPhone sales would enjoy sustained momentum into Apple's fiscal second quarter -- a quarter in which iPhone sales tend to drop substantially from the prior quarter. 

Apple's iPhone X being splashed with water

Image source: Apple.

The reality turned out to be very different. After reporting a 1% year-over-year decline in iPhone unit shipments during its most recent quarter, Apple is guiding to a substantial sequential decline in iPhone shipments. Moreover, Apple is forecasting an average selling price decline, as it expects a weaker product mix. That suggests that sales of its newest, priciest iPhone models will decline at a faster pace than will sales of older ones. 

In this article, I'd like to make the case that the delayed availability of the iPhone X ultimately hurt Apple's iPhone business in the current fiscal year.

Average selling prices could have been higher

Although Apple reported a stellar iPhone average selling price figure for the first quarter of its fiscal year 2018, driven in no small part by the introduction of the iPhone X, I think that the figure could've been even higher had the iPhone X been available earlier in the quarter. 

There were undoubtedly individuals who were in the market for new iPhones in September and October (though only October sales fell into Apple's fiscal 2018) who bought either the iPhone 8 or iPhone 8 Plus because that was all that was available.

Some customers may have had the luxury of being able to wait for the iPhone X to launch, but others may have simply bought the best that they could at the time to replace older iPhones and Android devices. 

Had those customers been able to buy the iPhone X when they purchased new phones in September or October, Apple's iPhone average selling price in the quarter may have increased, further boosting Apple's iPhone revenue growth. 

Underwhelming unit shipments

I also think that the delayed rollout of the iPhone X may have led to less-than-ideal iPhone unit shipments during Apple's most recent quarter. Adjusted for the fact that the first quarter of fiscal year 2018 was a 13-week quarter while the year-ago quarter was a 14-week one, iPhone unit shipments were effectively up around 6%.

This isn't a bad performance, but once again, I think Apple's shipment performance could've been better in the quarter had the iPhone X come out on time.

Apple says that it reached supply-demand balance for the iPhone X in the first quarter of fiscal year 2018, which could indicate that the delayed rollout didn't hurt Apple. However, I think the delayed roll-out may have ultimately reduced demand.

It's well known that Apple introduces new iPhones at roughly an annual cadence. Many iPhone buyers try to get the newest models as soon as possible to maximize the value that they derive from the device (especially if they upgrade each year). 

The potential buyers that like to have the latest iPhones as soon as they're released may have been discouraged at having to wait until November to buy an iPhone that would ultimately be replaced by a newer, better model in about 10 months. 

Those individuals may have ultimately opted to skip this product cycle altogether and wait for the 2018 iPhone models. 

Additionally, by beginning to sell the iPhone X in November, Apple shortened the amount of time that the iPhone X would have competitive advantages in the market. Typically, Apple's competitors launch new devices six months after Apple does and they sometimes introduce some of the unique capabilities that Apple did. 

By shortening that gap from around six months to around four months, Apple may have curbed its opportunity to gain market segment share in the premium portion of the smartphone market during the current fiscal year.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.