> writing generic code and having it run on anything.

That has been already done successfully by Java applets in 1995.

Wait, Java applets were dead by 2005, which leads me to assume that the goal is different.

> That has been already done successfully by Java applets in 1995.

The first video card with a programmable pixel shader was the Nvidia GeForce 3, released in 2001. How would Java applets be running on GPUs in 1995?

Besides, Java cannot even be compiled for GPUs as far as I know.