The Tomatometer would be worthless if Hollywood didn't consistently put out approximately 50% shit big budget movies. In the subjective aesthetic reality of Hollywood, Tomatometer rules because of it. Hearing "Avengers" is a 7.0 and "Under the Skin" is a 7.9 means less to me than a "shit/not shit" consensus, for what those movies are trying to be.

Tomatometer IS worthless in TV reviews and videogames. I assume "The Americans" the TV show is good, maybe a bit slow, I just don't watch it. I assume "Unbreakable Kimmy Schmidt" is probably pretty decent, don't watch it, yet.

I'm genuinely trying to work this out; something like "Big Bang Theory" is both 1)popular, 2)might get bad reviews. Old TV shows like "Alf" and even "Dynasty" could have gotten bad reviews, even if people liked them, and they got ratings? So what does that mean?

Most TV shows in 1990 would be panned by 'snob' critics for being shlock, while a smaller percentage of popular 2017 shows would be. Hollywood, as a functioning business, can't tell the difference between shlock and good, and why people like shit, and who likes shit. And that confusion leads to confused productions that suck, and get panned.