Actually it’s worse—you’d have to require people to file transactions that reduce the value of their house. Otherwise you could just sell the marble right after you’ve written it off to lower your tax burden. But these transactions are easy to hide, and even if their not hidden, they might be hard to adjudicate in some circumstances, and clever people will look for the hardest-to-adjudicate cases.
Actually it’s worse—you’d have to require people to file transactions that reduce the value of their house. Otherwise you could just sell the marble right after you’ve written it off to lower your tax burden. But these transactions are easy to hide, and even if their not hidden, they might be hard to adjudicate in some circumstances, and clever people will look for the hardest-to-adjudicate cases.