Money talks. Apple could’ve easily got what they needed from Intel but chose not to. It’s one of the many things that went backwards with the 2016/17 versions. One of the reasons the 2015 was so great was its excellent smooth UI performance, even on low-power integrated graphics.
Apple is not as massive a part of intel's market as you may think. Apple can complain, but they're literally 10% of intel's x64 CPU market in total, and 13" macbook pros or 12" retina macbooks are the majority of that with iMacs probably coming in third. You're talking about a small fraction of an already small segment of intel's sales. Intel likely don't care enough at this point - Apple are going to buy those CPUs for the 15" anyway, and just up-sell people to discrete graphics. Win-win for Apple. None of their competitors will offer anything different because intel is their CPU supplier also.
And yes money talks. This is why apple is starting to make their own GPUs and will end up with their own processors in the Macbooks. They could switch to AMD and get a better GPU for macbooks right now but they'd still face the same problem in trying to direct where AMD goes in the long term. If you want something done "right" (where "right" = what you want), do it yourself, etc.