I mean, it's feasible now; plenty of folks use vector rendering: Caching the result makes the CPU rendering much easier to deal with. The GPU would really help more with animations and dynamically constructed vectors.

In any case, I suspect something like lyon (https://github.com/nical/lyon) would be a better fit than pathfinder, which is both a) not super portable and b) very focused on rendering text, which it does very well.