Apple and Qualcomm don't sublicense so they are not really Arm competitors. Plus, ARM was always a convenient way to mutualise development costs without the risk of collusion. I am not sure it's changing.
You say people want to differentiate but Google constant failures to bring a state of the art offer with the Tensor shows that it's not that easy. Meanwhile Mediatek is competitive while remaining close to ARM design.
I don't think the market has changed that much on the high-end. The real question is how free will ARM be to export their future architectures. That's more where I see a risk.
That and the low-end being contested by Risk-V.