Why is it that tag team wrestling doesn't sell as well as singles? It's so rarely the main event of a A grade PPV (Survivor Series 2001? Survivor Series 92?), but the best tag matches are a bit more fast paced and there are a few more directions you can head in with more wrestlers. I know it's historically been big, but not much since the 80s.
First up, you should watch AEW once they get crowds back again if you're into tag team wrestling. Or a Mexican promotion.
Second, I think it comes down to the point of wrestling typically being a one-on-one grudge settled in the ring, whereas there's not too many two-on-two grudges. Plus Vince has deliberately killed off the tag team division many times now and it's viewed as a step down if you're a part of it.