It was only 30 days. Lost $400.
With those few miles driven, and the fact that it was 30 days, I would have challenged the drop in valuation. You didnt provide this information at the beginning, and normally when people come on here and post some variation of this question, they ordered 2 months ago, and put 900-1200 miles on the car since then and are surprised its worth less.
Tesla usually gives less for the trade than some other dealers because they are not interested in the slightest in the car, in most cases. Unless its a tesla, its going straight to auction (and even then, they still send many teslas to auction).
The flip side of that is, in some states you get credit against the sales tax for trading in a vehicle. In others (like mine) you dont.
If the original question is, is this a bait and switch, the answer is no. If the question is, does Tesla's software re adjust the value of the car after 30 days, the answer is yes, I believe it does.
Whether that changes value or not likely depends on the vehicle.