The repetitious use of the word "kingdom" in WT literature serves as one of several mechanisms to deflect attention away from Jesus Christ Personally, so as to concentrate on an abstraction. There are other mechanisms of course, the use of the hybrid word "jehovah" being another, and the focussing of attention on the FDS as a collective divinely appointed leadership also being one.
There are numerous examples of how this stress on the concept of the "kingdom" works:
1 The way WT literature treats Ps 72 is interesting in this regard. In recent years, since 1986 in fact, at least two publications have made reference to this Ps and explained it in terms of an abstraction, rather than as it is done in the Ps itself.
For instance, in the "True Peace and Security" book, published in 1986, we find this gem of wisdom, on pg 41: "With God's government by his Son Christ Jesus excercising dominion over all the earth, the ancient Ps of the Bible, Ps 72:7,8 will find fulfillment"
Nine years later, in 1995, referring to this same Ps, The book "Knowledge That Leads to Everlasting Life" says, on Pg 97: " Soon we will be able to rejoice not only because Gods Kingdom rules but also because it will bring blessings to the earth and obedient mankind - Ps 72:7,8"
However even a cursory reading of the text of Ps 72 tells us something different. Evidently initially referring to King Solomon, the Ps is also clearly Messianic in character, and rather than referring to an "it" that supposedly brings blessings to mankind, the Ps repeatedly refers to "HE" and "Him" as the bringer of these same blessings.[Vss 2, 4,6,7,8,9,9,11,11,12,12,13,13,14,14,15,15,15,17,17,17] As can be seen, if this Ps is futuristic in its application as implied by WT literature, then the future blessings mentioned in that Ps will be implemented by an individual Person, not an "it".
2 Perhaps the most blasphemous application of the "kingdom" into WT theology, and in direct contradiction of Jo 5:40, is an illustration found on the inside cover of the 1985 WT brochure entitled: "The Government That Will Bring Paradise" in this illustration, we see Jesus, surrounded by what evidently are His attentive disciples, pointing away from Himself to a glorious, radiantly crowned mountain, symbolizing God's Kingdom, as the bringer of "paradise"
There is not for a moment any shred of doubt in the minds of the WT leadership that the Kingdom as conceived by them is "A real operating heavenly government" [Knowledge book, pg 91] already constituted and prepared to take control of human affairs. In fact, it is so real, that those members that have died and gone to heaven already are, according to the Jan 1 WT of 2007, communicating with those members of the kingdom who are still alive here on earth. !!
Cheers