Yes, it seems to be a spiritual generation. Besides, we were already in historic times during the first century. Surely it would be noted somewhere by someone if all those people disappeared.
Yeah, would have been mentioned! Along with all the other fulfillments of Biblical prophecy—many many dozens of which have NOT YET been fulfilled as a matter of the historical AND BIBLICAL record.
Did any historians write about these things?
Luk 23:44 And it was about the sixth hour, and there was a darkness over all the earth until the ninth hour. Luk 23:45 And the sun was darkened...
Mat 27:52 And the graves were opened; and many bodies of the saints which slept arose, Mat 27:53 And came out of the graves after his resurrection, and went into the holy city, and appeared unto many.
Mat 27:51 and the earth did quake; and the rocks were rent;
There was no instant news back then. No CNN, or blogs, or youtube. News traveled by word of mouth or letter. There were no mega-churches, no large gatherings of Christians. How long would before any disappearances would be noticed? Would they think they just went on a journey, or to visit friends or relatives? How would the next city know of the disappearance of people two cities away? Would it be important enough to those left behind that they would send messengers to other cities to find out what happened? How many Christians were there? They were dispersed through all of the empire (1Pe 1:1). They met in their homes. How long would it take to gather all of that information throughout all of the empire? Would the leaders (anti-Christian at that) deem it worthy to make note of? They tried to cover up the resurrection of Jesus and say that his body was stolen. That myth was widespread among the Jews (Mat 28:15). Were people too worried about living their own lives to worry about, a few disapearances of their neighbors? It wouldn't be like today's world, where it would be known instantly that something was wrong. It could have been weeks before they realized people were missing from several different areas. There was panic in Rome over a food shortage in 70AD. Jerusalem was just destroyed and over a million Jews killed. Peter and Paul were killed in Rome, and other Christians were being burned alive and fed to animals etc. Would people just go out and say, "Hey, governor, I want to know where all the Christians went." Or would they be afraid, or, not even give it a second thought? Nero committed suicide in 68AD. There was trouble with 8 legions in 69AD who named a different emperor, and the then current emperor Galba was murdered. There were many things on the minds of the people in those days. Did the disappearance of some "Christians" rank high on their list of worries? The idol manufacturers like Demetrius would have been happy. They probably would have cared less. It wouldn't have been like in our time, where it would be all over the news within a day or so. Much different back then.