I noticed the off-site sales rep for local stores too....frustrating. Apple is slowly becoming like everyone else.That's great and welcome for a lot of people. From reading posts in this forum people can get the so-called mover discount combined with other savings to get the cost down.
But don't know if it's accurate or even necessary to say Best Buy always or often has more inventory available. Quite a few us, myself included, have posted on this topic we were able to walk in to an Apple Store and get what we wanted.
The online experience however leaves a lot to be desired. That you can't order anything online other than the base config for store pickup is more than inconvenient. The iOS Apple Store app doesn't even have the option for any config. And calling a specific Apple Store directly isn't even that easy any more. Unless you do some gymnastics with the options presented you're routed to someone off site which is why people are also probably not getting much luck calling ahead to check that store's inventory. They're getting someone somewhere who seems to only have access to the same thing we see on the online Apple Store.
Wasn't the case on Tue when I went to the NYC Fifth Ave store and bought the base dGPU model (2.5/512gb at $2499). Now I do see the online store showing it's available for pickup. But when I change the config to max it out (2.8/1tb at $3199) it still says ship to store even though it was one of the configurations they have in stock.store.apple.com showed it ready for pick up yesterday/today at my local Apple Store.