Yeh, exactly. A reasonable price and I wouldn't have cared much, I might've been a bit miffed, but I'd have paid it. As it is, even if they were to change their minds and come back to offering it for $15-20 a year you wouldn't be game to do it now - they're just as likely to make it $400 again in six months time. That's $400US too, more like $550AU.
Other sites still offer the same service for free without such painful ads, I would never still be using them if I hadn't started so long ago. But to kill 10 years worth of most forum pictures without warning and hold them for ransom at that sort of cost? They just put themselves out of business.