I think your last point is true, but not 100%. Apple for sure was unhappy with Intel. But I also think bringing the computer more in line with their line up of

I think your last point is true, but not 100%. Apple for sure was unhappy with Intel. But I also think bringing the computer more in line with their line up of phones and iPads also plays a role that it divorced from Intel. Apple, since the first iPhone, has been on a slow march to convergence. Everything on Arm is a major step towards convergence.