Didn't go through the thread entirely, but I had a pre order for a silver 12 pro (256gb) that was ordered on launch day. The initial shipping time frame was 10/24-11/02. On 11/02my card was charged, the shipping then updated to 11/03-11/05. I checked on 11/03, today, (hoping to get confirmation that it shipped) to find a new estimated shipping window of 11/27 - 12/11.
I called T-mobile where they confirmed the new shipping date is accurate. I cancelled the pre order because a lot of people are getting their phones by chance at the Apple store. A friend of mine works there and says that they typically get replenished daily in small amounts.
As for T-Mobile, they told me the intiial "Estimated Ship Date" essentially means that IF they can allocate one for you within that time frame, that they'll send it. In my case, they couldn't find one to "allocate" for me, so they put me into a new shipping window where they'll try again. Have to say it's the first time that I'm a little ticked off. It seems like it's a random grab bag of who gets one, and the shipping estimates aren't guarantees.
If anyone out there is still considering "pre-ordering" or waiting to get in line for the next replenishment of stock, I'd highly advise trying your local Apple store instead. As for T-Mobile, my local store said they aren't getting any in stock for first come first serve anytime soon.