I just want to say that if everyone only focuses on developing for GPUs just because they're faster, they might miss out on some cool speed hacks and math shortcuts that can be really helpful for people like me who don't have top-of-the-line hardware yet.
I fully support that. I think developers should work on slow computers (at least slower than average user's computer), it would force them to improve their code without relying on the latest/fastest hardware.