Here are others:
Lack of funding for entry fees, transportation to contest, floors, props etc.....
Lack of student commitment.
Lack of rehearsal space. Winter Guard already needs a gym and if your school is like ours, getting a gym is not easy.
If you want to participate in Indoor winds and have the funds, student commitment and rehearsal space then go for it and we wish you all the best.
Programs that don't participate do not have to give you a "Real reason" nor do they have to justify their decision.