I've heard that thought before, but unfortunately (For the JW's) it does contradict what is in print.
The identification of the Great Crowd in 1935 is still considered to be a, "Bright flash of light" and is regularly pointed to as a milestone in JW literature and the quotes I gave from JW literature above were all fairly recent (Within the last 10 years)
More importantly (IMO) it also contradicts Christian theology at a very basic level: Christians don't serve God specifically for a reward, but at the same time, without a reward, Christianity is entirely futile. (1 Cor 15:19)
Since JW's believe that virtually everyone regardless of whether they were "good" or "bad" will be resurrected and given a second chance in Paradise, allowing for the existence of "Other Sheep" in the Christian era who are not "Identical with that "great crowd"" removes the reward.
In practical terms what would this mean? Early Christians were willing to face death in the arena rather than worship one of the Roman gods. They were willing to do this because they believed that their salvation was at stake.
Consider what happens if we remove that reward: What if those that refused to worship the Roman gods are treated no different than those that did? What if those that died in the arena are simply resurrected to life on earth just the same as those who escaped punishment by burning incense to the Emporer's diety? What reason would there be for dying in the arena at all? --None whatsoever. Remove the heavenly reward and you remove the reason to be faithful.
The situation is virtually the same in a modern setting. Why convert to the JW faith? Why go to all the meetings, go out knocking on doors, refuse to celebrate holidays, etc.? JW's do this because they, like the early Christians, believe that their salvation is at stake. For non-anointed JW's that salvation is described at Revelation 7:9-10.
What happens if we remove that reward? What happens if JW's simply grow old and die and are eventually resurrected to life in paradise just like everyone else who never bothered with the JW faith at all? What reason would anyone have for being a JW? --None whatsoever.
Take for example, a fictional JW family. The grandparents were baptized as adults in the late 1930's and never considered themselves to be anointed. They were the only members of their respective families to become JW's. They've been dead for 20 years now. How is their fate any different than all their "Unbelieving" brothers and sisters and cousins that never bothered with the JW faith? In JW theology, there is no difference. They're all going to be resurrected.
Any way you look at it, an "Earthly hope" is not a doctrine that can be taught longer than about a generation or so. It's only the proximity of the end and the prospect of not having to die that makes it viable. Remove that reward and you remove any reason to be faithful.