Is it common for VC firms to keep pivoting their thesis and focus areas?

Now it seems “headless marketplaces” are where certain funds are doubling down on. Previously it was points, and before that generically consumer social.

Seems better to have a core thesis vs just ride the current hot thing?

cma.xyz. Founder /paragraph, ceo /mirror, previously at Google & Coinbase 

Separate between a core (hypo)thesis and derivative (hypo)theses. Pivoting in the sense of updating one's core (hypo)thesis is a rare thing, but happens, e.g. see Paradigm. Updating one's peripheral hypothesis based on new information is more frequent--and arguably a good thing. Frequently changing core theses--tricky