U.S. consumers are buying fewer smartphones and upgrading less often, a problem for device manufacturers and wireless carriers, such as Apple and AT&T respectively. The more advanced smartphones become, the less consumers feel the need to upgrade. Some consumers see the pace of innovation slowing, encouraging them to wait for breakthrough devices, and passing on the newest upgrades. Yet companies see a future in new services and technologies.

In the past few years, cell phone users have upgraded their devices at declining rates. Last year, there were 68 million upgrades in the U.S., a decrease of 9 percent from the previous year, according to UBS AG, a Swiss financial services company.

Companies such as T-Mobile and AT&T have introduced new plans and offers to entice customers with easy upgrade options, while others have added fees and lengthened the periods between upgrade eligibility. UBS anticipates upgrades to decline further in 2013.

The decline can be attributed to two trends. As smartphones near 70 percent penetration in the U.S. market, there are fewer consumers to buy them. And existing smartphone users are less motivated to buy new devices as the rate of device innovation slows.

There is an expectation of strong sales in emerging and international markets, with industry analysts predicting 48 percent growth, reports The Wall Street Journal. Despite this potential growth, Apple stock shares fell 19 percent and Samsung dropped 15 percent as investors fear weak device sales.

Device makers and wireless carriers see opportunities as newer technologies and services emerge, such as connected vehicles, wearable devices and increased use of the mobile Internet. Satellite TV provider Dish Network has been buying wireless spectrum in hopes to enter the wireless industry, and SoftBank, a Japanese telecommunications company, recently bought control of Sprint Nextel for $21.6 billion, hoping to develop payment and media services for the mobile Internet.