We did back in 2007: https://en.wikipedia.org/wiki/Open_Graphics_Project

And there have been some others as well: https://en.wikipedia.org/wiki/Free_and_open-source_graphics_...

Recently https://www.furygpu.com/

Part of the problem is that every ASIC manufacturer (and indeed each fabrication process) has a different toolchain with a different set of primitives for circuit design. Yosys and other open tooling for FPGAs has helped a great deal in lowering the barrier to chip design and by association reuse of circuits. But every ASIC, at the moment, is tied to some vendor's PDK. Here's the one Google open sourced for Cypress Semi's SKY130 process node: https://github.com/google/skywater-pdk