I'm guessing from your post that you are still in highschool. I may have an explanation for you. Our school put Chicago on our season for next year, and then found out that the producers haven't released the amateur rights yet. Meaning, they want to tour it and keep it in the professional theatre circuit. This may be a reason that you couldn't do it, and they figured that you guys wouldn't understand.
On another note, I did a converter and figured out that 2000 pounds is a little less than $4000 USD. To me, that's not a LOT of money to do a show. You can't spend all the money on the choreographer or you won't be able to build a set, costumes, or rent lights or anything else extra you may need for the show. It gets pretty expensive, depending on how you do things. And Chicago is not a small show.
And even though Box was a little pessimistic, I think he was on to something. You are a student and I'm sure it was very difficult for the producers/directors to make the decision to cancel it, but I'm sure they have their reasons, and they probably aren't going to back down on their decision. I hope maybe I helped a little. I, too, am anxious to see what everyone else has to say.