Why is isothermal amplification not as commonly used as PCR?

One reason why isothermal amplification is not as commonly used as PCR is because it is more expensive. Isothermal amplification involves multiple amplification cycles and each cycle requires a fresh polymerase containing mixture to be added to it, followed by a chemical denaturation step. This can make isothermal amplification much more expensive as compared to PCR. The higher cost acts to its disadvantage.