Does the early intervention not cure autism or it can prevent some behavioral aspects of the disorder autism as not to become a major problem?

yes early intervention definitely helps to achieve better life skills for children under ASD

early intervention can reduce the harmful behavioral aspects of the disorder autism

Early intervention does not cure Autism. It does however reduce behaviors and increases the ability to progress in daily life routines.  

Autism can't be cured, it only be managed.

Early intervention play a major role in managment of autism. In early stage intervention help in improving the development and understanding of immature brain and baby has a more pick up power as compared to an adult and abnormal behavior are still not developed.

Early intervention increases the chances of better management of challenging haviors