If he exists, no. If a radiologist tells an ignorant person, do not go into the x-ray room because the radiation can cause severe genetic damage, then the person can either believe him and obey, or he can simply go into the room and be there comfortably as long he wishes since he can see or feel nothing. Satan exists, but hides in darkness. He will manifest the moment when someone decides to willfully live a spiritual godly life.
(Here is a question. If Fr. Amorth knows all of this, then why doesn't he go ahead and "clean house" at the Vatican? If it is true, then he should do something about it instead of just writing about it. I think he sounds like he is nuts.)
Fr. Amorth is doing his part by exposing the truth. It is not easy to clean up everything at once.
A diligent policeman may have information about the thieves, the drug peddlers, the mafias groups, terrorists, etc., from many sources. He does doesn't go and clean them up in a jiffy.
There are many procedures to undergo, media, politics, permission, authority, power, etc., and each thing has to tackled in a differently based on relevance, dangers, complexities, etc., in their respective time. Some may be tackled quickly, some may take a long time, and somethings may continue persist despite all measures. It is akin to nation's fight against criminals, it will never end as long as sin in this world exists, but fight nevertheless we should.
There are so few active Catholic priests working as exorcists that often, people who need their services, have to travel great distances, even out of the country.
As far as I know, it is up to the bishop of each diocese to appoint an exorcist. Exorcism can take weeks or months, may not be fully complete for greater than a year.