Aside from pissing off those who just took delivery -- anybody who ordered but has not taken delivery will no doubt cancel or demand the new price -- this is also a hit for all current Tesla owners, who will now see a big drop in the used price of your car when you are ready to sell it.
A few months ago, used cars were hard to find and you could sell your 3-year-old Tesla for more than you paid for it. Now, with a new one at this price, and a ready supply, the drop in value of my used Tesla is pretty painful. Of course, had I sold it back then, I would have to have replaced it with other than a Tesla since those had a 5 month wait for delivery.