This "declining West, rising Asia" is way overblown. Do you know what it really is? It's a tool by the Western elites to keep the Western mass in check and in control, while tapping the vast labor reservoir in East Asia. In other words, it's a very clever form of (economic) imperialism on East Asia brilliantly utilizing the human nature across different civilizations.
Transfer of power from America to China isn't just a intra-civilization power shift. It'd be an inter-civilization power shift, and there're just too many factors to be done readily, if it is doable at all.
By Asia, you precisely mean China, and China, and the East-Asian civilization as a whole, must pull off an improbable task to replace the West as the world's leading civilization. Japan can't do it, neither Korea, nor Taiwan, nor Singapore, nor Hong Kong. In fact, if you omit Japan and China from "Asia", it becomes laughable, as all the other nations are mere satellite states that could and would belong anywhere, leaning to whoever is currently in charge. Japan is America's faithful beta. Only China remains a probable contender as it is rising against the West since the whipping of the two Opium Wars in the 19th century.
Study the East-Asian history and value system. You'll be hard-pressed to believe that China can avoid being another Japan--an East-Asian nation adopted the Western ways that plateaued after catching up because they didn't have their own blood temperament to pioneer and wage wars for causes.
Instead of focusing on "Asia", focus on China. It's a vast civilization state, and it'll be some interesting x-factor in the global stage as the years roll on. Get ready to exploit it: The Chinese mass has been exploited by both the internal and external forces for millennia, and those who know how have much to gain from fucking China. Many have known tender Asian pussy is a very sweet and delectable thing to rape and ravage on. The Chinese elites have known this for ages, and so did the outside elites. It's hard stopping history from repeating itself.
"I may betray the world, but I won't let the world betray me."** -- Cao Cao, the antigonist in
Romance of the Three Kingdoms, one of the Four Great Classical Chinese Novels, perhaps the most prominent and quintessential.
**(translation: I may fuck the Chinese mass in the ass, pussy, and mouth, but I won't let the Chinese mass fuck me in my ass.)
Chances are, China will start to make good, if not great contributions to the advancement of the human civilizations in its own ways. At times it's been at the top, and there's no reason why it can't be again. That doesn't mean the West will just 'tank', however. In fact, the human competition mechanism being what it is, rise of China will force the West (reads America) to rise to the occasion to counter the competition, lest it wither and die.
Let the competition roll on.
"In the practical art of war, the best thing of all is to take the enemy's country whole and intact; to shatter and destroy it is not so good."
Sun Tzu
Oh my, there's some serious heat coming from China...