so if this DEX continues I just want to ask how is the development of the central exchange, will the trading volume decrease and switch to all DEX?
Not all CEX will decrease in volume.
There are traders that would like to stay with the use of CEX because they're convenient and easy to use. The two will co-exist and it's all up to us whether we like to use both of them.
But usually, we do use both of them.