As for freedom, Janis Joplin called it another word for "nothin' left to lose." Whether or not they have tasted it, I'm sure that China doesn't want to be India.
I'm sure India doesn't want to be China, either. In any case, that comparison is rather a fallacy that assumes the only difference between China and India is their form of government, ignoring massive differences in history and culture. A better comparison would be China and Taiwan.
Yes, and they put many people out of work. The only way to get worse than China's air quality is to breathe China's polluted air and smoke cigarettes on top of that (as 50% of Chinese men do). Yet because the government makes 7% of its revenue off cigarettes, it has been extremely reluctant to crack down on smoking. In a democracy, public health advocates would be able to oppose the tobacco lobby. Nearly half the cigarettes in the world are smoked in China. That's a big negative when considering the "air quality" actually going into people's lungs.
Certainly autocracy has some benefits when it comes to the construction of infrastructure, but modern China is approaching the limits of what can be achieved with more infrastructure. Returns are diminishing. After a certain point more roads, railroads, airports and dams just stop contributing as much to growth as they did initially. Also let's not forget that the current wave of Chinese economic growth was unleashed not when the government decided to start spending on infrastructure, but when the government decided to liberalize its management of the economy, allowing market forces a greater role. In a way, it was the market forces that financed the infrastructure spending to begin with.
This is a valid point, but there may be economic advantages to switching to a democratic system of government in the long run that are underestimated as well. The Great Firewall and the heavy censorship of the Internet stifles innovation and makes it harder to do business in China. The government's one child policy (supported by the CPC family planning bureaucracy) will create a country where 1/4 of the population are retirees and that will heavily tax the economic system. And then there is the militarism that comes with an autocratic government. The more other countries see China as a threat, the less likely they will be willing to cooperate with China and share technology with it, the more difficult it will be for China to invest abroad, and the more China will have to spend on defense. If China gets into a war with another country, its economy could be devastated. Over the long run all of these factors will be more important than building infrastructure.