Chinese are not allowed to buy stocks etc, so real estate is the only alternative for them. Hence the massive overbuilding. All for speculation, people did not intend to actually live there. Just hoped to sell it on with a profit
This is a totally misinformed, idiotic, and obviously incorrect statement.
Have you not heard of:
The Beijing Stock Exchange.
The Shanghai Stock Exchange.
The Shenzhen Stock Exchange.
The Hong Kong Stock Exchange.
All of which are open to, and actively traded by, Chinese investors. Not to mention the many insurance products sold in China, backed by Chinese listed stocks, available to 1 Billion+ Chinese who live in China?
What you may be confusing yourself with though, is the restriction on capital outflows from China, which makes it harder for some Chinese to buy assets overseas. Obviously though, there are many ways around this, as evidenced by the many Chinese owners of foreign real estate. (That money flow from China will increasingly move into Bitcoin, over time, for obvious reasons).
Where you are partially correct though, is that if locally listed companies are not seen as viable investments by Chinese (ie distrust of Government influence in the economy, poor corporate governance, and unethical or fraudulent conduct by directors, then yes, real estate becomes a popular alternative (especially in a market perceived to be rising fast when combined with Chinese values associated with owning a home).