I think it is well known and proven that people upgrade every two years when the contract expires. My claim is only that the built-in battery contributes to thi

I think it is well known and proven that people upgrade every two years when the contract expires. My claim is only that the built-in battery contributes to this, you are free to disagree, but it is difficult to prove either way. Your ifixit links certainly do not prove battery replacement is easy. Specialist tools are involved, this is how iFixit makes its money.