In this article, Jameson discusses a conflict that science fiction authors face. The conflict is closure. It seems contradictory when making up a narrative in the future that is completely imaginary to have to end it. The fact that there must be closure in a novel, if it is to follow the typical narrative style, means that science fiction novels tend to end confirming that the imaginary events were false.
For example, if we look at The Strange Case of Dr Jekyll and Mr Hyde, at the end we see the demise of both main characters. Stevenson came up with an extremely provocative and creative storyline to explore the idea of the other, but because it is a narrative he is writing, he must kill off these two characters at the end of the book. This provides closure and containment and succeeds in limiting the characters to the pages of the book.
Wells does not fully conform to this so-called obligation for closure in The Time Machine. In the ending of The Time Machine, the time traveller has set off on another expedition and it is 3 years on and he has still not returned. It seems that Wells has addressed this conflict of closure and science fiction novels by giving a sort a resolution and then taking it back. Closure happens when the time traveller has returned from the trip and is at the dinner party with his alien flowers. This final trip that he never returns from however, challenges this resolution. Wells does not want to end his science fiction work with a resolution so he almost does (to lend the novel a typical structure of beginning, middle, end) and then he takes it away.
Wells is teasing the reader. Is this idea of other universes purely a topic of intellectual exploration that happens at dinner parties or is it real. Is it just another example of a group of intellectuals bringing together their many different opinions? This is how ideology is created according to Jameson. Wells is trying to blur the lines between false consciousness and science and I think it is his ending that ultimately lets him succeed in doing this.