Had it been a hoax it should have died out sooner.
But surely the key point of a hoax is that it is a
deliberate deception - in other words the hoaxer knows that the story is one that they have made up and isn't true.
That isn't the same as a genuine belief in something that isn't true.
So I doubt there are many people who think that christianity arose due to a
hoax - in other words those actually present at the time made up stuff they know to be untrue. Possible of course, but completely unnecessary for the development of christianity later. I suspect the most likely explanation is that later authors etc embellished, exaggerated and/or misinterpreted what had come from earlier. So an empty tomb is interpreted as a resurrection (when that may not be what those there at the time thought), a dream like vision is exaggerated to a real physical Jesus with wounds you can push your finger in, a vague recollection passed down through several generation is embellished to create a detailed (too details to be believable) narrative.
Now unless those people in the late 1stC through to the middle 4thC (note that none of them were there at the time of the purported resurrection) genuinely knew that they were creating something untrue - in other words they knew there was no resurrection but made stuff up nonetheless, then there is no hoax. What you have is genuine believers creating stories and documents that support their genuinely held belief, regardless of whether what they believe is true or not.
It is only a hoax if the people transmitting the story know it to be untrue but make up stuff to deliberately deceive. I see no more reason for that to be the case for the resurrection than for a belief that the earth was flat or the sun went round the earth - genuinely held beliefs that were passed on for generations, with stories to embellish etc. Neither is true, but I see no hoax there as I don't see evidence of people who knew the earth was round or went round the sun deliberately creating a deception.