this will sound like something from acient aliens but I assure it's not. some of this is speculation but it's based on the most solid science we have with some help from some science that isn't set in stone yet. so let me start by speaking about two scientific theories that would support this.
Einstein created a what would be a working theory of time travel. he called it a rosen bridge and it would use wormholes to create a fold in space and time linking two points of time together and in theory one could go back in time. the problem is that the energy needed to break through space time would negate all life on any planet it was tried on. keep that last part in mind.
String Theory of time and why the univrse would not allow for a paradox to happen. String Theory holds that there are multiple lines of time running parrallel to each other and that each time line is set in stone so to speak. meaning that you could go back in time and stop the assassination of president lincoln BUT you wouldn't be saving our time lines lincoln because you cannot change our timelines past. thus you'd save another timelines linclon a time line in which you were supposed to go back in time and save him from that bullet. the time line in other words would simply shift to another time line where these events already happened in the past and all memory of the events would be strutured for that time line. in other words we would never know of or remember the other time lines history. keep this in mind too.
So I think the Philidelphia experience actually took place. I think it worked. I think it desotroyed our planet and everything on it in creating said rosen bridge. due to that negation of life on this planet we instead shifted to this time line where the experiement never took place (officially) or did take place but failed to work at all. I can't prove this as we cannot create a rosen bridge here on earth especually not with the tech we have now and string theory has yet to be fully be prove as the way that universe as we know it works. but if either or both of these are true then it's at least possible that this is not the orginial timeline we lived in since the dawn of our universes time. and sadly it's because this crazy experiment actually worked. now in our timeline now Al Belick is an absolute fraud but this was the thoughts that came of my study of sciences being pushed now but have yet to be fully substantiated. take it as you wish.