Especially earlier on, web components were implemented without incorporating some of the major feedback from developers. What resulted was a low-level tool with some really awkward warts and APIs that was more-or-less unusable. (hence, one of the reasons why when web components discussions come up, lit is always mentioned since it needs that extra layer to paper over some of the warts)
TL;DR: it replaces some of the bad parts of Angular/React/etc. with its own set of bad parts that become more obvious only once you get deeper in.
Especially earlier on, web components were implemented without incorporating some of the major feedback from developers. What resulted was a low-level tool with some really awkward warts and APIs that was more-or-less unusable. (hence, one of the reasons why when web components discussions come up, lit is always mentioned since it needs that extra layer to paper over some of the warts)
TL;DR: it replaces some of the bad parts of Angular/React/etc. with its own set of bad parts that become more obvious only once you get deeper in.