The Apple Watch wasn't always the king of smartwatches. Here's how it went from unpopular fashion accessory to conquer Fitbit and everyone else.

• The Apple Watch is the most popular smartwatch in the world, but that wasn't always the case.
• It struggled to win over customers when after launching in 2015 and lagged behind Fitbit.
• But Apple in 2016 redirected its focus on fitness instead of fashion and sales started pouring in.

The Apple Watch has come a long way since it hit six years ago.

It was initially deemed a flop in 2016 and failed to win customers over in the months after it launched.

Now it's the most popular smartwatch in the world, with a 55% market share that dwarfs competitors like Google, whose $2.1 billion Fitbit acquisition gave it an edge starting in 2019.

Facebook is reportedly ready to launch its first-ever smartwatch in 2022 - it has its work cut out for it, given Apple's dominance.

Here's how Apple's smartwatch went from floundering to flourishing in the consumer wearables market.

Fitbit was once leading the race

Fitbit launched in 2007 and had set the stage for what would later become the booming wearables market when the Apple Watch launched in April 2015.

With a price range starting at $349, it required an iPhone to operate and was the company's first new popular product debut since the iPad in 2010.

Some, like Jean-Claude Biver - the CEO of legacy watchmaker Tag Heuer - doubted that it would endure over the years.

"Can it be repaired in 1,000 years or can it be repaired in 80 years?" he told CNBC in 2015. "Can your children wear the watch? No, because it won't work anymore. The technology will be gone." Less skeptical observers expected the product to be the death knell for existing market players like Fitbit.

But consumers were slow to adopt the Apple Watch as a must-have wearable. Some early reviews pegged the watch as hard to understand how to use, with a poor user experience.

The analytics firm Slice Intelligence released data three months after the Apple Watch launch that showed tanking sales. In mid-April, the company was selling about 35,000 watches a day. By July 2, Apple was selling around 5,000 per day. Analysts also noted that demand for the company's smartwatch had fallen sharply since it launched.

As Fast Company reported in July 2015, the Apple Watch appeared to be flopping.

Fitbit sold 21.4 million devices in 2015, which is also the year it went public, according to Wired, and 22.3 million in 2016. Apple shipped 7 million Watches from April to November of 2015, and Canalys estimated that the company sold 11.9 million units in 2016, as Fortune notes.

If the Apple Watch were to succeed, many speculated that it might just need time before it would become a hit - and that's exactly what happened.

Apple Watch began to pick up steam in 2017

Apple started focusing on fitness and health features in its watch instead of merely the fashion appeal of it.

Watch Series 2 was unveiled in 2016 with water resistance and GPS that people could use without an iPhone. Later versions had similar features, like being able to track your menstrual cycle and detect abnormal heartbeats.

Suddenly, people were clamoring for the products, which could efficiently track their health and fitness activity instead of merely serving as a luxury item. The company began to reinvent how people perceived watches and showed they could be even more useful than solely telling time.

It even leapfrogged Rolex as the number one watch in the world in mid-2017.

In September 2017, Apple unveiled its Apple Watch Series 3, which allowed users to make and receive calls and stream music without their iPhone.

Fitbit had previously held the record for the most wearable devices sold by a single company within a fiscal quarter, shipping 6.1 million units in Q4 during 2015. But in the fourth quarter of 2017, after the Series 3 was released, Apple shipped 8 million smartwatches and shipped 18 million units throughout that entire year.

"Apple has won the wearables game," Canalys senior analyst Jason Low said in early 2018, according to CNET.

Apple has since blown past legacy Swiss watch companies, like Swatch, TAG Heuer, and others, who are struggling to compete with the phone giant's hit fitness-oriented smartwatch. Apple shipped an estimated 31 million units in 2019, compared to the 21 million shipments that Swiss watch brands were collectively estimated to have made, research firm Strategy Analytics said in an early 2020 report.

Apple released its now-discontinued Watch Series 4 in 2018, featuring a bigger screen size and Apple Watch Series 5 in September 2019. It debuted its Watch Series 6 and Watch SE in September 2020.

Apple still 'in the early innings of the Watch'

Apple may be the world's leading smartwatch maker but Cook said in an April earnings call that "the number of new people that are new to the Watch is almost three out of four" and wearables remain "a long way from being a mature market."

The wearables market may be young, according to Cook, but it's crowded - Apple faces competition from the likes of Samsung, Fitbit, Fossil, Garmin, and many others. And soon, maybe Facebook.