No mandarin and Cantonese are completely different spoken language.
Yes. However, they are all languages of China.
Dialects differ from the common language and official language. You cannot simply compare them. Comparing Cantonese with Mandarin, or Taiwanese with Taiwanese Mandarin, is not appropriate.
Don’t you really believe that the culture and Fujian have similar cultures after 70 years?
The culture of Taiwan after the civil war ended isn’t even that similar to what it is today.
Taiwan culture certainly differs from the Mainland culture and Fujian culture, and I do not deny that. China is vast. The cultural gap between Fujian and Taiwan is smaller than that between Fujian and Northeast China (Manchuria). Yet, which region shares the same government with Fujian?
The Taiwan culture of 70 years ago is also distinct from the present-day Taiwan culture, and I will not deny that either.
But I am talking about something more fundamental, more traditional—the kind of thing that silently permeates your cultural heritage.
Language, writing, festivals, religion, food, traditional architecture, customs... These elements are extremely resistant to change; they form the very foundation of Taiwan's cultural "tower." All developments are built upon this bedrock.
Moreover, cross-strait cultural exchanges have not been frozen in time since 70 years ago. Indeed, political atmosphere and levels of economic development do impact cultural exchanges, but such interactions have persisted and continue to this day.
Mainland China possesses a massive economic scale and an extensive cultural industry, which consequently produces an immense volume of Chinese-language cultural products. In contrast, the scale of Taiwan's local cultural industry is relatively limited. More importantly, as people in Taiwan also use the Chinese language, they encounter lower barriers when accessing and enjoying the Chinese cultural products from the Mainland.
Let me guess you think Okinawa and fujian have the same cultures because of fujian’s influence on karate right?
Okinawa? It is true that Okinawan culture has been influenced by Chinese culture. But what is the ethnic composition of Okinawa today? Is there a clear "Okinawan ethnicity"? No, they have all become Japanese. Colonialism and World War II essentially wiped out the "Okinawan ethnicity."
Now, are Okinawans' language, writing system, religion, and customs—these cultural "foundations"—more similar to China's or Japan's?
What about Taiwan? 96.2% of Taiwan's population is of Han ethnicity. Han? Do you remember what I said? This is also the majority ethnic group in China, accounting for 91.1%. Oh, Taiwan is even more "Chinese" than the Mainland.