The sight of the tricycle rusting away in the stream made me think of a person coming home to find their favorite toy somewhere familiar and getting flooded with memories that they’ve been too busy to think about. It doesn’t have to be an object. It could be a familiar smell or a color. A place where some small event happened. All of these things trigger a strong emotional response as the memory plays over in our minds. Somehow though, they never really mattered until they were forgotten and became a memory.
I can see the protagonist of Fallout 4 (“The Wanderer”) having a more stinging emotional belt in the face with the resurgence of his/her memories. These items have been here for more than 200 years. But for him/her, all the little things like this would be fresh in thier mind, like they happened yesterday. Because for him/her, they did.