Arm is important, but for R & D. The impact of not having Arm will take a long time to be felt. The same for a lot of the others you mention. Not having a supply or Intel and AMD CPUs would be felt much faster and would be harder to find replacements for.

ARM doesn't just do R&D, they design full CPU cores. Until recently, Qualcomm's cores were ARM's reference design with their own extensions on top. It's only since Oryon that their CPUs are more dependent (the tech was acquired through their Nuvia acquisition).