It seems obvious to me that with any type of artistry, there is fashion. With fashion, there will be trends that become popular and fade, and there will be icons of previous trends that remain. I think it's safe to say most of us still love the Talking Heads or Prince, but maybe we no longer care for A Flock of Seagulls or Wham!.
I think the elitist mindset misses the nuance between design skill and general novelty (I do not mean "elitist" here disparagingly, only that the mindset presupposes is a single vector of "goodness"). I think there is a significant amount of overlap between something being considered "good" and something being considered "interesting." That something being interesting requires at least a non-trivial amount of novelty means that success will require some experimentation. When a novel approach is compelling, we will see dozens of folks iterating on it. Iterations on a theme often exceed the interest of the original, but after a good amount of time it becomes increasingly difficult to surprise, and the trend fades.
This is normal and is a perfectly reasonable outcome in artistic creativity. It also leads to apparent groupthink, which I think is probably better explained by the genuine interest of novelty, following by waning of interest. When interest in a trend wanes, it's often quite clear who created the consensus iterations on the theme. There are two parallel tracks of consensus: novel ideas and best iterations on those ideas. Trends rise and fall because they are interesting and then become boring. If you have an elitist mindset, then this looks like groupthink overtime, but if novelty is part of a complex goodness, then you genuinely have courses that change in their level if goodness over time.
Sure, critics often get the zeitgeist wrong (Psycho, Fight Club, and even It's a Wonderful Life were all panned by critics), but the audience themselves can actually get things wrong too (American Beauty, Love Actually, and Crash [2004] are all movies that most people like, and now have no idea why they liked them). This is difficult to explain if we have a single vector of goodness, but if we have a dynamic model of goodness that is based as much in human experience as it is in the thing itself, the all of these trends and groupthink are trivially explained by certain pieces of are having different impacts on people at different points of time. I fully understand that this is an unsatisfying explanation of aesthetics, but it can still be a useful one, again, if we think of critics as proxies for peoples various and contrary tastes, instead judges of goodness. Even if critics disagree, we can still find critics we generally agree with and use their opinions. We do here, however, lose the benefits of aggregation and/or consensus as a guide.