Solving the problem of composability of visual components on top of the existing DOM leads to chicken-or-egg problems like getComputedStyle/offsetTop mentioned

Solving the problem of composability of visual components on top of the existing DOM leads to chicken-or-egg problems like getComputedStyle/offsetTop mentioned in that Mozilla blog link someone else referenced. DOM is a crufty stateful beast, and enhancing it is hard which scares me away. Beyond that, the Web Components spec seems geared for coarse-grained components - like a widget or a panel. I could be wrong about this, I admit, my experiments a year ago with Web Components were short lived when I saw how much got polyfilled on Firefox. Anyhow, React is a javascript library exercise rather than a retool-the-DOM exercise to me, and that's a big reason I appreciate it. It offers data binding, rendering, templating, and true-componentization all in one package - and it supports legacy systems. I think there's an answer in Web Components for all of those things, including legacy support up to a point with polyfills, but it wasn't cohesive nor easy to roll things. I think with lots of tool support, perhaps a compiled language targeting the Web Components spec, it could be just as easy to roll Web Components as React Components.