The software that builds and displays the experience is the browser. Most webpages could be cut by 90% and be visually and functionally indistinguishable. For 90% of the last 10%, the functionality cut out would improve the user experience, especially on mobile.

..and the server, protocols, and language used to build that web page. It's not like a powerpoint presentation.

Which only highlights the point of how overengineered it is. You shouldn't need (and in fact you don't need) several-layer tall stacks of programming languages and support equipment to render something that's less functional than a PowerPoint presentation.