Japan still has many great electronics manufacturers able to design and produce classy and powerful smartphones. Sony is just one of those, and that is why Samsung and Apple have relatively small, if not negligible, marketshare in Japan.
Taiwan has HTC and more and those vendors offer far lower prices than Samsung and LG.
China was once a large cheap source for Japan, Taiwan, and South Korea to produce motherboards, laptops, mobile phones, etc. But while other East Asian nations still depend on the mainland China for cheaper land and labour, Chinese hardware and software companies founded and managed by Chinese born in Beijing and Shanghai are leading their domestic market which is vast and growing fast. One of them is Tencent, the software company of the world's largest and most influential mobile messenger. It's difficult for any Chinese smartphone manufacturer to enter South Korean market, but it's also difficult for any South Korean smartphone manufacturer to compete against a successful Chinese vendor in their domestic market. Since Samsung makes most of their profits out of expensive models like Galaxy S4 and Note 2, most Chinese consumers will buy from much cheaper devices from domestic vendors.
South Korea has Samsung Electronics, LG Electronics, and Pantech of Hyundai and SK Telecom. Though they are outsourcing to China, South Korea still has a lot of factories and workers to make phones.
The United States market is owned by Apple and no other company can threaten Apple's ecosystem in the foreseeable future because more than half of the US voters PAID to own Apple proprietary contents - music, ebooks, applications.
Nokia never was good at design and marketing to enter any of the East Asian markets.
I'm not sure why Google really bought Motorola. The patents might have been helpful, but those alone couldn't have justified the cost and distraction. I thought Google could try to make better phones out of Motorola. Motorola's Atrix was my first Android phone. Google failed, and why would Microsoft succeed with Nokia? HP bought Compaq many years ago. I had at least one of HP's Compaq laptops, a very nice tough one with good keyboard and speakers. It would have made much better results if HP's shareholders just gave Compaq US$100 billion in cash so that the latter could buy HP later. There are books on why M&A on a very large scale often results in disaster for everyone involved.
During the past few years, I read thousands of articles on Nokia and BlackBerry on hundreds of dedicated smartphone websites and others targeting investors and industries written by reporters and analysts partly because that was one of my jobs. Two things were common in all of them: 1. They were concerned and worried. 2. But not about products and productivity.