Hi Clete,
If we extend anything far enough we will eventually expose its weakness. I think this is true of classical science. However, this does not stop us from trying. It is only by exploring our theories and pushing them to the limit we will eventually come to see the need for a different approach.
Actually, weather forecasters sometimes get it wrong in a two day forecast but they don't just give up and go home. Quantum computers are a long way off so all they can do is work with the knowledge they have.
When it comes to computer modelling all they have are bits, 0 or 1 , on off, true or false; whatever you want to call it. In an odd sort of way the scientific method mirrors this technology.
Naturally, any climate scientist would rather have a small quantum computer than a state of the art super computer.
At the moment, and possibly for a long time to come, we are paying the political price for being in the middle of 'a change over' so to speak.
Just my opinion
Tut
P.S. "Weakness of will". Actually I was just being polite. I think you estimation is probably closer to the mark