I could see your point, but there is just one problem. How do you account for the writers of the New Testament teaching about truth, love, honesty, giving, etc. all based on lies? Why would they suffer hardships like beatings, starvation, shipwreck, imprisonments, and finally execution for nothing but lies? What you are saying doesn't make sense, and raises more questions than it answers.
The only logical explanation is that the fulfilled prophecies really did happen. Jesus actually rose from the dead. He performed miracles, and He forgave sins. He forgave sins then, and He can still do it now. My sins are forgiven, are yours?
Please note that many cult members will die for their faith as well. But they die for something they believe in, not for something they have actually seen. Muslims, Mormons, Jehovah's Witnesses all die for their faith. But the New Testament believers died for what they saw and believed, not for what they believed only. That is a big difference. The N.T. writers died claiming that they had seen the risen Lord. The cult members die for what they believe, and we know that believing doesn't make it true.