Samsung's Android-powered Galaxy Note 5. Photo: Samsung.

Android's dominance is indisputable. In the second quarter, Alphabet's (NASDAQ:GOOG) (NASDAQ:GOOGL) mobile operating system powered 82.8% of the smartphones shipped globally, according to research firm IDC. Apple's (NASDAQ:AAPL) iOS came in a distant second place, with iPhones accounting for just 14% of global smartphone shipments.

Although it may seem ubiquitous today, there was a time when Android was far less dominant.

Source: IDC.

Conquering the U.S.
The first Android smartphone was released in the fall of 2008, more than a year after the iPhone's debut. The HTC Dream was a T-Mobile exclusive in the U.S., but it eventually made its way to other carriers in Europe and Canada. Sprint launched its first Android smartphone, the HTC Hero, in the fall of 2009; AT&T rolled out two Android-powered handsets early in 2010. But if it weren't for Verizon, it's possible that Android wouldn't be where it is today. Big Red put more weight behind Android than any other carrier, securing the rights to the Droid brand from Lucasfilm, and spending an estimated $100 million advertising the original Motorola Droid as the best alternative to the iPhone.

Android is the most popular mobile operating system in the U.S., but to a lesser extent than in other countries. At the beginning of 2010, Android represented about 7% of the U.S. smartphone market -- today, it's just over half. As its popularity rose, Android attracted the support of developers. In April 2010, the Android app store added its 50,000th app. Now, Google Play offers around 1.6 million -- more than any other app storefront.

Google gains a key ally
Android's market share gains didn't truly accelerate in the U.S. or globally until Samsung adopted the platform. Samsung had been a modest player in the mobile phone market before the iPhone's introduction, and initially attempted to fend Apple off with Internet-connected touchscreen phones like the Samsung Instinct. In October 2009, it launched its first Android-powered smartphone, and in 2010, it unveiled the original Galaxy S.

Samsung's smartphone shipments surged by more than 300% in 2010, when it captured 7.6% of the global smartphone market. Samsung's Galaxy SII and Galaxy SIII were even more popular, and lower-cost variants helped Samsung succeed in emerging markets. Samsung's market share has declined in recent years, but early in 2012, the Korean tech giant was making almost one out of every three smartphones shipped globally. In Europe, it captured almost half the market, and in China it made almost one in every five smartphones.

About half the Android devices in use in 2013 were made by Samsung, according to OpenSignal. That figure has declined, but is still near 40%. Google's CEO, Sundar Pichai, once likened the relationship between the two companies to the long-running PC alliance between Microsoft and Intel.

As Samsung's market share has declined, so too have its mobile profits. HTC has been hit even harder, and it appears to be on the precipice of collapse. Yet new Android vendors have risen to take their place. Chinese firms Huawei, Xiaomi, and Lenovo are all Android OEMs. They, along with Apple and Samsung, round out the top five smartphone vendors and are growing even more rapidly.

But is it too dominant?
But Android may, in fact, be too successful. Although Google gives Android away for free, it benefits, as Android owners are encouraged to use Google's many Web services. Unfortunately for the search giant, Android's dominance has attracted the interest of regulators.

In 2013, Chinese government officials warned that, with about 90% market share, Android was far too dominant, and the country had grown dangerously dependent on Google's operating system. The Chinese government declined to take action, but it served as an interesting announcement. More recently, both European and U.S. regulators have set their sights on Google's mobile operating system.

These challenges may prove to be an inconvenience, but they seem unlikely to dent Android's market share. With BlackBerry on the verge of launching its first Android smartphone, almost all credible competition (with the exception of the iPhone) has been wiped out. Apple may make some modest gains in the quarters to come, but unless it launches a low-cost iPhone (something it has stubbornly avoided), it won't capture the emerging market masses.

Perhaps one day we'll move on to a different computing platform. Until then, it's an Android world.

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.