I think for Larrabee it was intel experimenting to find other markets for their Atom cores, and if there was market for it they needed to have the tenacity to cultivate it. Similar to how nvidia took huge amounts of time establishing GPGPU, CUDA, then machine learning, through to reaping the rewards over the past few years.

2010-2011 was also the time that AMD were starting to moan a bit about DX11 and the higher level APIs not being sufficient to get the most out of GPUs, which led to Mantle/Vulkan/DX12 a few years down the road. Intel did a bit regarding massively parallel software rendering, with the flexibility to run on anything x86 and implement features as you liked, or AMD's efforts for 'fusion' (APU+GPU, after recently acquiring ATi) or HSA which I seem to recall was about dispatching different types of computing to the best suited processor(s) in the system for it. However I got the impression a lot of development effort is more interested in progressing on what they already have instead of starting in a new direction, and game studios want to ship finished and stable/predictable product, which is where support from intel would have helped.