You dont seem to understand that we all die, even Jesus died. But he was resurrected. As we will be who believe. JEsus demonstrated these miracles because he loves us and also so that we know hes come to save us. Why we dont witness resurrections now, its because it isnt the end of the age yet for us. The entire creation is waiting for redemption, groaning for it.
Nobody has said Jesus heals everyone, because not everyone believes in Him, and even when he was on earth he couldnt get to everyone. Also the fact that many people dont have or are ignorant of his healing power, they havent got to that anointing. I wouldnt say its lack of faith, its just Jesus knows peoples hearts and what people need most is healing in their hearts and souls not their physical bodies, because what glory is it to have a perfect body in the flesh yet not a heart after the Lord. And sometimes its better to be taken out of this world than to be in it.
Also, Jesus resurrected body...it had scars on it! In his hands and feet. I think many people dont quite understand that healing doesnt necessarily mean we will all have perfect faculties in the flesh forever right now since that part of us wont inherit the kingdom anyway. Otherwise people could tell you were a christian because youd be walking round never aging, never getting sick, strong as an ox, and outliving everyone. Smith wrigglesworth was a man God had anointed to go and heal yet even his own son was deaf. And kathryn kuhlman, had great healing miracles yet even she didnt know why God would heal some people and not others.
It might be timing, it might be heart condition, you cant judge automatically and say its lack of faith. Even martha got antsy when Jesus delayed coming to see her sick brother Lazarus and by the time he did, Lazarus was dead. Yet his delay was deliberate..and a greater miracle followed.