though i share some of your sentiments, i dont really think the MPD fancam views is really that much of an indication of her popularity, and especially the recent ones since people are saying that the views are frozen.
ever since the beginning of sixteen i have been sceptical of how jyp and jype treats tzuyu, and i am pretty much not surprised anymore that she gets no lines in their songs (titles or bsides). and though she is improving, her vocals are not a level where she should get more lines, especially considering where jeongyeon and chaeyoung are at in all of this.
all in all, i feel you, but relax its not that serious