Yes, this is something I wish was elaborated upon more. Entanglement isn't some strange process that rarely occurs. It occurs with all particles of matter at

Yes, this is something I wish was elaborated upon more. Entanglement isn't some strange process that rarely occurs. It occurs with all particles of matter at once due to the fact that the wavefunction that describes a system is a function of all particles. It just so happens that if some portions of matter are well isolated from another portion, then you can approximate the overall wavefunction by writing it as the product of two independent wavefunctions of two subsystems. When there are noticeable effects that deviate from this approximation, that's what most articles are referring to as "entanglement".