Selling accounts is only allowed in a few specified sections. It's not specifically stated that it's allowed here, therefore it's not allowed.
Also, with the trade limitations in the actual game, there would be no way to transfer the wealth off one account to another, which makes it even riskier and less appealing for the buyer.
The original owner of the account could, at any time, recover the account with the wealth still there - assuming the person who bought the account didn't waste/delete things.