Wonkish,
You put it very well.
The "static" nature of CBO "analysis" has been under attack by economists for several years.
CBO counters that it is impossible to accurately project such changes.
The bottom line is the CBO is consistently wrong!
And honestly, I'm not really disputing that the CBO is...well...wrong...frequently...even consistently if you like...and you spelled out pretty decent reasons why it often errs. If asked why the CBO isn't accurate, I'd rattle off many, but perhaps not all, the aforementioned reasons. That said, I wouldn't make the leap that what the CBO does (forecasting, whatever) is malicious, or fraudulent. Just on many occasions wrong, and there is a difference.
I wouldn't say its malicious. But they know their going to be off in the same direction every single time and they don't care. So call what you will, but its not accidental.
If they are consistently wrong in the same direction, then that makes their errors predictable and thus something that can be adjusted for because they are reproducible. Conversely, if they keep adjusting their methodology in search of being more accurate, their estimates become less useful.
Which would you rather have, a clock that is consistently 15 minutes slow, or a clock that is always within 5 minutes of the correct time, but you can't be sure if it is fast or slow?
