As mentioned here, I feel like the marketing for THP wasn't very successful. Even though the band seemed very excited about the album, there was barely any promotion done prior to its release, both on their side and Warner Brothers'. I think the lack of music videos, THP album-related LPTV episodes, a proper lead single (with the whole disaggrement between them and the label about the lead single, and the way GATS was released, it didn't feel like there was a proper lead single for this album), and to some extent, the lack of THP songs at live shows, lead to a lack of interest from casual fans during the THP cycle.
If you ask me, this is how they should've done it:
April- Final Masquerade + music video
May- Rebellion + music video
May/June- Release GATS, UIG and Wastelands on iTunes
June- Album release
September- GATS music video (a proper one)
January- UIG music video
+Play 5 songs from THP at every show.