Here is one perspective on the recent US stock market losses against its gains over the past few years. Note that the stock market valuations have doubled, as US companies bought back their stock (instead of increasing wages) to raise their share prices.
Attachment 6134

Now look at China's market over the past few years.
Attachment 6135

The global economic demand for goods has been slowing for the past few years, and China's manufacturing output reflects that, as did its stock market. however, the Chinese government decided that reducing the economic expectations of its workers was politically untenable, and instead encouraged its citizens to buy stocks, thereby creating a bubble. That bubble is bursting.

After China lands flat on its back, the US should devalue the dollar to make US goods cheaper for the world to buy. Making these goods would boost the amount of work that US workers would have, and would keep the US economy going strong and would support wage increases. But politicians will probably not do that, because they are surprisingly affordable to corporations that would just as soon see US workers idle in order to keep wages low, because multinationals are just as happy to manufacture in other low-wage countries.