They've always had unlocked XR phones. What's the big deal about throwing away the sim that they included?
Actually it depends. At least in the US, when the XR was initially launched it was the carrier model that Apple were selling and yes they are unlocked if and only if you purchase them outright or if purchased through iUP. If you buy it from Apple and you finance it through the carrier's financial plan then it's locked. Only difference between the carrier model and the sim-free model is that the carrier model comes with the sim card while the sim-free model does not.
That's the thing, nothing has changed. You can't buy an unlocked phone on a carrier plan, so if you wanted an unlocked phone before you could simply pay full price for any of the carrier models and get an unlocked phone. The difference being they came with a sim card that you could simply throw away.
In a way that is correct. However, the part number for sim-free model and the carrier model is different. Regardless, yes it's the same A model number. However, some people, like me, prefer to buy an actual sim-free model over a carrier model.