The town falling apart isn't 'symbolic' of anything. The story premise was that since she was brought into the Haze artificially she got looped in with Hibiya and Hiyori's Haze the same way Haruka/Konoha did. Hence the line from the song "Rioting people, a sobbing girl…" which is accompanied by the image of the classic blue and pink spots that normally represent Hibiya and Hiyori.
The town falling apart was the end of the loop she had entered during and because she was artificially stuck into their loop she wasn't going to enter the second loop in the same manner of repetition that Hibiya would. It is stated in the song Kagerou Days "With that, like a cricket’s sound being disturbed, the light blue of summer darkened away…" Hibiya basically just passes out and wakes up with the previous day repeating.
Because Hibiya followed the standards of normally entering the Haze, the loop was customized to him. Takane/Ene would have to go through the day and upon the town falling apart she would wake up the next day in the same situation in the same spot as the day before to continue the loop. The crumbling town was the destruction of that specific loop that would carry into the next loop upon rebuilding the area from the beginning.
The reason that this wasn't repetitively shown is that she exited the Haze before the loop completely ended, and through which she entered the computer and then the story continues into Ene's Cyber Journey (Ene no Dennou Kikou).