Of all the strange new worlds Star Trek explores, it's the non-capitalist future, without poverty, that people have the most trouble with.
And I don't really buy that whats objectionable is the lack of explanation. Its the boldness of saying humanity has to grow up to reach the stars. And that growing up means going beyond religion, nationalism, and capitalism.
What is more likely is a mass extinction, huge population loss, and crawl back out of another dark age. But I prefer Roddenberry's worst ideas to more of the same.
Maybe some of the posters here can't envision a world beyond their own dispossession?
"If they had asked," Lededje told her,"I might even have told them; I was running away to the Culture because I heard they'd escaped the tyranny of money and individual power, and that all people were equal here, men and women alike, with no riches or poverty to put one person above or beneath another." Surface Detail by Iain Banks page 159.
I think the crucial point here is that dispossession actually implies empowerment of a different kind. I don't need to wield more power or own more than my brother or sister to be happy. I am actually more happy when I do not have to fear that somebody wants to take more power or possessions for him- or herself at my expense.
And no, none of this implies that nobody strives for excellence.