It's almost like having double frame buffers for 720p or larger, 16 bit PCM audio, memory safe(ish) languages, streaming video, security sandboxes, rendering fully textured 3d objects with a million polygons in real time, etc. are all things that take up cpu and ram.
I didn’t realize web browsing in Chrome required fully textured 3D objects. Not to mention playing 720p video with PCM audio in a separate app doesn’t grind everything to a halt.
well the gpu doesn't care if it's 2d or 3d, but you are rendering a whole bunch of textured triangles.... (separated into tiles for fast partial or multithreaded re-rendering), and also just-in-time rasterizing fonts, running a complex constraint solver to lay out the ui, parsing 3 completely separate languages, communicating using multiple complex network protocols, doing a whole bunch interprocess communication in order to sandbox stuff
I will run any game at 60fps if it was designed for this exact machine that does nothing but play games designed for it and is also 16-bit with pixel graphics and also has low quality audio and also fits in the memory of the cartridge
WebGL means the browser has access to the GPU. Also, the whole desktop tends to be rendered as a 3D space these days. It makes things like scaling and blur effects easier, among other benefits.