Yeah its weird that Texas is "different" in this regard? The process is the same even in other states; I've never seen a Tesla store with a stock of cars just there on-site ready to buy that day, you always order online (or, I suppose, the salesperson orders online for you, and maybe that's illegal in Texas? I dont know).

And, frankly, this is how most new car purchases work. Every one I've purchased or been a part of; they don't end with you driving off the lot in a new car, they end with you waiting a week or two for the car to be delivered. I imagine some dealers have a limited stock of new cars in common configurations, and you could drive off in one of those, but that's the minority of purchases in my experience.