It was my understanding that the Post-Mao creation of free-market-like conditions in China was an admission by Communist leadership that the Hegelian model of history could not be short circuited (as Lenin and Mao attempted), and capitalist style economics was required to industrialize, but that the capitalist economics was a temporary solution.
I could be mistaken though, and I'm curious why you thought they arrived there by luck.
If you're China in 1980 or 1990 (ie third world infrastructure), vast infrastructure spend will faciliate your decades-long growth explosion. Without that, you can't become China of 2019, you can't actually go from a $400b economy to a $14t economy. The ports, roads, rail, bridges, utilities, energy generation, et al. is a requirement and produces extraordinary returns in a context like that. It drastically boosts economic productivity and raises your maximum output potential by a lot.
As another recently discussed (on HN) example, Romania has had one of the world's fastest growing economies in recent years. Economically it's attempting to push into a solid middle-tier economic nation, in the footsteps of countries like Poland, Chile or Slovakia. Romania simultaneously has a horribly lagging roads network that is in desperate need of expansion and improvement. It's very likely that properly building out their roads infrastructure would help facilitate their economic boom continuing; and that not doing so, would act as a serious point of friction on growth long-term. You can't get to $25k GDP per capita, with roads built for a $2k GDP per capita economy.
(See also: Stalinist industrialization. It was easier for central planners to focus on the hypothetical exponential impacts of "building machine tools to build machine tools", or to focus on building as many T-34 tanks as possible, than to actually design a self-sufficient war economy, which they never really had--there was a very strong reliance on imports of Allied food, radios, and other small goods.)
Only if you have competent leadership (which they seem to have right now). When you have a bad leadership and a dictatorship, there's no safeguard to prevent a total disaster to happen. The main advantage of a democracy isn't the power to the people but the separation of power, that's sometimes the last safeguard available to prevent a country to collapse.
Centralized / decentralized planning and democratic / autocratic decision making are orthogonal concerns.
Thus China currently has a 400% debt to gdp, private firms defaulting and failing while state firms hoards and makes inefficient investments, most of the free world economies aligning against China, more than 1/3 of rich people in China wants to/ are in the process of leaving, etc
The ECB monetary politics was never meant to "save" any specific country (a whole system, maybe. You could argue abut this).
On Beijing giving away money to Italy: it is a commercial deal we are talking about. The political implications of this deal are way more complex than a passing statement.
I think saner governments manage that pretty well, they know research is good and beneficial so there's no questioning.
Meanwhile in the USA, coal is or is not a health risk as policy dictates.
What China learnt in the past 4 decades was how to manage the beast, not behead the messenger and have an effective planning anchored in true market signals.
Another point worth mentioning is that the Four Tigers are working with a planning and investment horizon of 30-50 years. Since they don't have to justify every four years about what they've been up to, they can be more effective in chasing bigger investments that have a longer-term ROI such as research, education, strategic industrial branches.
Now how do you compete with that?