Which part has been wrong, exactly? Who created the mess? As far as I can see, a lot of things have been wrong, but a lot of things have been learned as a result.I dunno. "it's not all been perfectly understood" reminds me of "there's more work to do", a standard by which the goalposts are forever shifting wider. Can you imagine showing up in 5th grade to Mrs Smith back in the 70s and 80s without having done squat on your homework and saying "But Maam, don't hold to me to this! I got more work to do!" That would go over well.
How about something subtle like, "Wow, we've been really wrong for decades on this and need to own up to the mess we've created"?
While I have my pet peeves, I do believe that even a science as dismal as economics proceeds in small incremental steps.