And if that property falls to $900,000? Now you owe $1 million on a home worth less; literally throwing away $100,000.
If the value of your asset falls, you've lost net worth.
It's preposterous to claim that, even though the price of your home has fallen by half, and you are servicing the mortgage on the old value, that you haven't lost anything. Or that the fact that you can offset capital gains with capital losses somehow makes a plunge in value "worth it".
"Paper losses" are losses. The value of the asset isn't based on the price you paid.
until the bubble pops up, like it did in 2008, but it comes back up so it's a rather temporary set back. Also, rents rarely come down, so most often the property value decline is temporary, or it is another opportunity to buy when things are in water - when there is blood in the streets, there is money to be made.