That was my first thought as well. A lot of current web development relies heavily on code generation then has obsfuscation and compression slapped on top leading to complicated structures. Then on top of that, more code (client side/JavaScript) reconfigures everything again. You end up with fairly complicated html/css/JavaScript to wade through.

For better and worse, 5-10Mi isn't uncommon for a web app.

Instead of trying to go "bottom up" and, effectively, do what a browser engine is doing in reverse, it seems easier to go "top down" like a human does and go off the visual representation.