Doing high-performance 3D rendering on the Web has always been a tricky proposition.
WebGL, in its quest for programmer familiarity and cross-platform ubiquity, adopted the API of OpenGL ES. As such it has never been capable of exploiting the full power of the underlying GPU, even as desktop APIs like DirectX 12, Metal, and Vulkan debuted and became popular. Furthermore, Apple has been slow to build out full support for WebGL 2: as of this writing, it remains an Experimental Feature in Safari).
Fortunately, the situation seems to be changing. After over four years in development by a working group in the W3C Consortium, the WebGPU API is hopefully on the cusp of stability and broad availability.