Because at the end, Stewart has conquered his vertigo--which symbolizes his fear of marriage and commitment. When he steps out on that ledge on the belltower, we know he will return and marry Barbara Bel Geddes. The film is about conquering fear.
That's one interpretation...among many of this haunting film.
Scottie does overcomes his vertigo but not the need to avenge himself on the figure who has betrayed him.
When Scottie reunites with Madeline/Judy his obsession, the only woman he loves, he is unable to conquer his emotional shock of her deception. Eventually he is forced to watch her die too. The pain of her death touches his twice, because he feels responsible for two deaths - not stopping Gavin from killing Madeleine and putting Judy into a position where she falls off the top of the tower to her death.
As for conquering his fear of marriage - the sinister character of "Midge" (Bel Geddes) is probably what made him fear marriage in the first place.
No I cannot see this as an "inspiring" film per se...although it is among the pantheon of superbly crafted works of art in the film world.