Why cant DNA polymerase from organisms be used in pcr?

Many DNA polymerases from organisms are not suitable for PCR because they do not possess the optimal features required for the enzymatic reactions involved in PCR, such as high processivity, thermostability, and fidelity. PCR generally requires a DNA polymerase that can withstand the high temperatures used during the process without denaturing. Taq polymerase, isolated from the thermophilic bacterium Thermus aquaticus, is commonly used for PCR due to its ability to function at high temperatures.