Well, of course our feelings about whether the ending of this novel is affected or not will vary from person to person. However, let me point out a few of the ways in which the ending gives us a powerful symbol of hope for humanity. This novel above all is a rather pessimistic vision of a future world where changes in humanity (namely the blindness that has struck everbody) has rendered humans unable to rule the earth. Natural selection and evolution therefore have placed the triffids in the prime position because of the way that they have adapted to not being able to see and humans have not. The very harsh and cold rules of environmental Biology are shown to therefore impinge upon humans.
What makes this even worse is that Wyndham very clearly lays the blame for this on humanity. Let us remember that the triffids only developed from humans messing around with nature, and the meteor shower was the result of a malfunctioning satellite that was made for the purpose of biological warfare.
However, in spite of this rather grim and unyielding message of human mistakes and Biological laws that demote humanity, the novel is shown to do something to restore hope in us. There is a certain balance in the way that, although science got humanity into this mess in the first place, science looks as if it may be able to find a way to defeat the triffids. The Beadley community at the end of the novel is placed in stark comparison with other communities shown to us in the novel as it is founded on rationalism and science rather than anachronistic religious ideas, authoritarian or feudal groups that we see at various points in the novel. If there is hope for humanity, we think that its chances will be much higher with the Beadley group than with any other remnants.