What's wrong with using a 3d accelerator and falling back to CPU graphics if needed? Pixels / joule is orders of magnitude better on an iGPU than on the CPU. (Which can matter over a 8-12 hour editing session, maybe.)
Modern IDEs don't use 3D at all, nor do they use the sprite-like 2D graphics that GPUs excel at and that can accelerate, e.g. mobile touch- and swipe-based UX. The main thing they do is font rendering, and accelerating that on GPU while keeping visual quality unchanged is quite complicated. The graphics pipeline doesn't really help all that much.
Modern IDEs don't use 3D at all, nor do they use the sprite-like 2D graphics that GPUs excel at and that can accelerate, e.g. mobile touch- and swipe-based UX. The main thing they do is font rendering, and accelerating that on GPU while keeping visual quality unchanged is quite complicated. The graphics pipeline doesn't really help all that much.