There are so many assets that can be used for the speculations. But speculations are not for the development of the economy because it give no useful products.
Speculation is only money flowing, but nothing more for real economy. Real economy needs a real goods.
People who are interested in speculation are not interested in the economy development.
Good liquidity is a good tool to avoid speculation. Also to avoid speculation it is necessary to suggest something useful for people.
When there is a real and useful product there is less place for speculations.
Also there is less speculation when are assets a backed by real goods because all of them have their real market price.