there are a lot of thread s and arguments around the 587/607 issue, it can be a bit confusing, and for those of us still in, like me, to help others, it would not be a topic I would choose first. It was something I found out, after I awakened, before I simply brushed it aside, as something like worldly chronology against biblical chronology. IMHO to be ready for this issue, you have to be awake first, unless you are a real history buff..
anyway, there may be another take on this matter:
lets say, JW are right, the kingdom was erected in heaven in 1914. What was the proof for it ? The only proof, witnesses have, is the composite sign in Matthew 24, Luke 21, Mark 13...the explanation in connection with Revelation 12: Satan was thrown down from heaven, and caused trouble for humans, starting WW1 and all followoing developments, deseases (spanish Flu), etc...
So think about it: The only "proof" besides the wacky chronology, for the last days are signs, which are caused by the devil...hmmm....
So the fulfillment of divine prophecies were depending on Satan. So satan, surely at least as smart as Miller/Russel/ modern JW, must have been able to calculate his time of being thrown out from heaven. Since he didnt want to spoil the game, he just waits until that year, and then goes ahead, since he knows now he has a short time (he didnt realize this 1913 or earlier for some reason, maybe he lost his calendar ?) and he starts WW1 and all the bad things, that signify the last days. He apparently was happy to fulfill exactly the prophecy.
If the big issue is really beween Gods woshipper (JW, or Bibel students at this time) and the Devil, then one could at least expect from the Devil to start the troubles earlier or later than 1914, just to make sure, the prophecy fails...
Actually thinking about it, Revelation 12 refutes the idea of being able to calculate the begin of the Messianic reign, since only when the Devil is thrown out, he knows, he has a short time. This only works, if it really surprised him....
just some ideas.....