This is why 1914 is so important. Their "proof" for 1919 is 1914 and the subsequent "captivity", which they connect to all sorts of scriptures that have nothing to do with it. To the WT, the Kingdom was set up in 1914. Jesus needed to pick his earthly representatives at that point. He picked the WT because, well, they were lesser of all the evils. It seems that they were "sincere" and "on the watch", so they were it! But they were filthy with Babylonian-the-Great-like practices. As the WT says:
*** w55 5/1 p. 266 Part 9—Postwar Revival of the Witnesses ***
For example, up to and including their 1918 troubles these witnesses of the Most High God still trusted excessively in so-called “character development,” indulged in considerable creature worship, accepted earthly political governments as the “superior authorities” ordained of God (Rom. 13:1, NW), and thus were held in fear of man, particularly civil rulers. Also they celebrated some pagan holidays, such as Christmas, they used the symbol of the cross as a sign of Christian devotion, the name of Jehovah they had in the background, and organizationally they continued to practice the democratic style of local congregational government.
So Jesus sends them off into a Babylonian-like captivity for year. This is why the leadership was sent to prison. It wasn't Satan. It was Jesus... he was "refining" them. They emerge in 1919 all cleansed and ready to serve! Well, not really cleansed... I guess you can say they were "cleansed".. since they still used the cross and celebrated Christmas into the late 1920s.... In any case, if you loose 1914, you loose 1918... and 1919... And of course, you loose 1914 if 607 turns out to be false... or any of the other speculations in between 607 and 1914, like the year-day "principle".... *shrugs*... Its a mess....