Why does the story end with the description of Mr. and Mrs. Samsa noticing Grete's blooming beauty?

The novella The Metamorphosis by Franz Kafka was originally written in German in 1919. During the time period in which it was written, men were often the primary source of financial income. Thus at the end of the story when Gregor is no longer in the picture as a contributor in the family, it is only practical that Grete finds a man that can support her. As stated in the text,

While they amused themselves in this way, it struck Mr. and Mrs. Samsa almost at the same moment how their daughter, who was getting more animated all the time, had blossomed recently, in spite of all the troubles which had made her cheeks pale, into a beautiful and voluptuous young woman. Growing more silent and almost unconsciously understanding each other in their glances, they thought that the time was now at hand to seek out a good honest man for her. And it was something of a confirmation of their new dreams and good intentions when at the end of their journey the daughter first lifted herself up and stretched her young body. (Kafka)

When Grete’s brother, Gregor, dies, she no longer has to worry about him and can focus on herself and the future. Furthermore, Gregor’s parents see Grete’s “blooming beauty” as an opportunity to find someone to take care of Grete while also financially helping them out as well. From an analytical standpoint, when looking at the language of the text, Grete is compared to a blooming flower. Remember, Gregor is described as being transformed into some type of insect in the story. These descriptions might bring to mind the idea that insects tend to eat away at flowers. When Gregor dies, he is no longer "eating away" at Grete, and now she can be lifted up and stretch her young body, similar to the way a flower blooms.
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