I haven't seen the evidence yet that China still wouldn't have achieved its economic advancement if it wasn't an autocracy (though that's because you could never prove it). China was the biggest economy for most of human history, it was only in the 1800's that began to change, you could argue it's just a return to form, it's also much easier to catch up with current economies, most countries which are poorer have higher growth rates which means they're catching up with the west. There's a great video from Gapminder that shows you the growth over the last 200 years. China also does especially well as they're happy to pillage intellectual property, and can't really be hurt for doing so. The video is here:
I fundamentally think that you can have good and bad democracies, as well as good and bad autocracies, there is plenty of evidence for countries that have done poorly under autocratic systems (China included suffered ups and downs until ~1970). I think the U.S system of democracy is horrendous though and needs a massive overhaul. Any system needs change and I think we should be looking at how we could make democracies work much better in the 21st century with all the technology we have available.
Fundamentally though I'd always want to live in a country where I can choose to remove my leaders if they were incompetent or even worse dangerous/genocidal, what China is doing to the Uighers is absolutely terrifying and I'd never want to live in a country where I could end up in that situation, in healthy democracies where there are protections against the tyranny of the majority such things aren't possible, and I'd happily have my country be behind the curve economically if needs be to avoid that fate (as mentioned before it's easier to catch up anyway).