The Carlsbad zillow link shows there are problems with very high end rentals. It was listed at $6595 on 8/28, and a bunch of price cuts followed. It’s empty now, and who knows how long before.
If this were 2 units half each half its size, they would have rented easily given how ultra tight the market is.
When you get to that price range, renters also have high expectations and complain more.