Look, the People's Republic of China has spent much of the past half century trying to destroy and reject thousands of years of history and culture. People couldn't eat the foods they had eaten in their ancestral homes (starvation, communism and sparrow murder put a damper on that), they couldn't celebrate their ancient Chinese holidays (Chinese New Year was banned, amongst others) and the very fabric of traditional society and Confucian ideals were painted as evil (teachers were called enemies of the state, reading and learning anything non-state sponsored pre-Mao was considered subversive). Consider a hundred years before that, China was in constant state of war and unrest. The last 150 years has been hard on China and its people and the average member of society couldn't be bothered to preserve culture and identity when they were busy just trying to stay alive.

Since the 90s it's been getting better but in many ways Chinese culture has been fragmented to the point of losing pride in its identity. Hell, what is a Chinese identity anymore? I don't even think the PRC knows because they constantly have to keep the socialist aspect in mind. Contemporary China has been a giant human experiment. Mao and the socialist initiatives have manipulated and molded China and its people into what it is now. The party is so insanely anal about who or what to push out as a reflection of "Chinese culture" because Chinese culture was so vilified for so long, it's only relatively recently they even considered the question. That's why cultural exports are as shallow and dull as OP spoke of; Beijing has only selected "safe" bets because anything authentic, underground or perhaps truly contemporary is cause for alarm due to the government's inability to control its influence.

China is huge and the whole history of two Chinas and persistent diaspora has not helped matters. There are Chinese people all over the world now and all of us hate each other, or at least one group of the "other". Add in the one child policy, and you create more fissures in society. Chinese people are selfish. We are driven by money, status, and social ranking. Call the reason war or social upheaval or political affiliation, but most Chinese people are driven only to better themselves and not the greater good of nearly anything, least of all promoting China to the world in an authentic and genuine manner. I say this as a Chinese person who has grown up in Chinese culture and earns a living trying to get people excited about China and Chinese culture.

For two summers, I trained Hanban guest teachers before we delivered them to Wyoming or whatever random state in the U.S. All of them came because they wanted to immigrate to the US to earn more money. That was my number one question: how do I stay in the US after my contract is over. Second question was, how do I bring my family over. The textbooks were insanely dull with boring generic topics that elicited no critical thinking or cultural analysis. It literally didn't teach anything beyond the language, pandas and for older kids, historical figures, if at all. Unmotivated teachers teaching an aimless, directionless and unengaging curriculum. No wonder Confucius Institutes aren't doing well.

It's a combination of these reasons why China and its government has struggled to spread its culture out in an effective and engaging way. (a), The PRC doesn't even really know what is "true" Chinese cultural identity because they still are trying to maintain a fine mix of Mao ideals, and (b) Chinese people have been conditioned over generations to look out of themselves and their family so there's no universal pride or motivation to promote the greater good.