The difference is that you can actually go to a dealer and buy those other cars right off the lot if you so desire. Can't do that for a Model 3.

Not only is that not relevant to the original statement, it's almost certainly not true. And getting a base car at base car price is likely almost impossible.

The Audi and Lambo aren't in as high of demand as say, a Ferrari 488 (or whatever the latest mid-engined model is, I've lost track), but you can't actually buy a 488 if you don't already have a history of Ferrari ownership. So, while I doubt Audi and Lambo have the same restrictions on who they 'allow' to buy their car, good luck buying one off the lot or in any reasonable timeframe.