Hi Len...the "great crowd" is defined by their participation in the Great Tribulation and who survive Armageddon. Those who identify as the "great crowd" before Armageddon are thus prospective members of the great crowd.
*** it-1 p. 997 Great Crowd ***
It thus appears that the “great crowd” is formed of those persons who have been preserved during that time of wrath and who have been able to “stand” as approved by God and the Lamb... The sum of the evidence, therefore, points to the “great crowd” as representing all those persons who are not of the heavenly “bride” class, or 144,000 sealed ones, but who stand approved at the time of the “great tribulation” and are preserved alive on earth.
*** sl chap. 17 p. 324 par. 24 The Creating of “New Heavens and a New Earth” ***
With eager anticipation, the “great crowd” of prospective survivors of the “great tribulation” are also awaiting the “new heavens and a new earth.” This “new earth” will be the new human society living under the “new heavens.” (Revelation 7:9-14) Just as Noah and his family survived the global deluge and formed the nucleus of the new human society on earth, so the “great crowd” will survive the approaching “great tribulation” and will form the permanent nucleus of the new human society, the symbolic “new earth.”
*** g77 9/22 p. 27 Does It Matter What You Wear? ***
A “great crowd” of tribulation survivors are depicted as “dressed in white robes,” indicative of their dignified, clean appearance before the Most High by reason of their faith in the shed blood of Jesus Christ. (Rev. 7:9, 13, 14)
*** jv chap. 16  p. 243 Meetings for Worship, Instruction, and Encouragement ***
Particularly beginning in the 1930’s, prospective members of the “great multitude,” or “great crowd” of other sheep, began to manifest themselves. (Rev. 7:9, 10, KJ; John 10:16)
*** w07 2/1 p. 21 par. 19 Jehovah Is an Appreciative God ***
Of course, Jesus’ love for his anointed followers is also extended toward his loyal “other sheep,” millions of whom now make up the prospective “great crowd . . . out of all nations,” who will survive the coming “great tribulation.” (John 10:16; Revelation 7:9, 14)
The problem is that the Society teaches that the great crowd has made its appearance beginning in the 1930s (see for example 10/1/1978 Watchtower, p. 12; 5/1/1992 Watchtower, p. 22; 2/1/1998 Watchtower, pp. 18-19, etc.), but if all of those who identified in 1935 as prospective members of the great crowd die without experiencing Armageddon, then none of them were really members of the great crowd, which means that the great crowd couldn't, in fact, have made its appearance in 1935.