Is working for these companies just worth the prestige for some?
If you have skills, experience, or for a fresh graduate an interest, in what in the US would be considered a mainstream enterprisy (Java, Angular, .NET) and passable English or Japanese language skills, you can get a position in development with a Fortune 500 or as a contractor to a F500 without too much difficulty. Normal 9-6, 5 day work week, public holidays plus 10-15 days discretionary holiday per year, stability over fast-pace, middle class income (8,000 Yuan per month for 0-2 years experience, 20,000 per month in a Tier-2 city for 5 years experience; for reference rent for a newish 2 bedroom apartment within 20 minutes walk to the office would be about 3000 Yuan per month).
The BATs (Baidu, Alibaba, Tencent) pay more, 2x or 3x, and are the glamorous places for fresh grads to work. Good luck getting in though.
Want-to-be BATs are probably the worst employers. They lack the pay and prestige of BATs, lack the stability and sane working culture of F500s, and tend to have terrible management that lack conviction and realistic goals. Without a BAT or F500 early in one's career, it's hard to break away from want-to-be-BATs.
I know nothing about Games development, so no comment there.
There is a big age ceiling. 15 years experience doesn't pay much better than 5 years experience and will often be met with questions about why not able to move into product ownership of management, but that's another topic. Working in a Tier-1 city will mean rents are way higher, purchase of property probably unattainable, and wages probably less than double those mentioned above.
I hope that answers part of your questions.
And that when a trained factory worker salary is about to break 15000...
It's there a lot of collaboration with Japan in Chinese IT? NEC?
Is product ownership or management seriously considered a better job in China? At almost all places I worked at in EU middle management/product ownership is considered a less desirable position.
And in this case, only a handle of companies in China offer work-life balance, most of which are owned by foreign capital (e.g. Google, Microsoft and IBM). They are very hard to get in, even harder than their US counterparts, because of the much smaller headcount and much larger pool of candidates.