Prices in expensive parts of SD will be affected by reductions elsewhere because the premium, relative to other areas, will remain somewhat constant.
Only the super rich or the stupid fail to do some sort of cost benefit analysis when buying (“But honey, it costs an extra 200k for that school district. Is it really worth it? This other school district is pretty good. And we can have a nicer house!”)
Oh, wait. You all think it is different in Carlsbad. It’s the weather, baby! And hey, they aren’t making any more land!!!