This doesn't sound right. Who's doing the replacement ... a dealer, 3rd party, yourself?
First of all, I haven't heard of any problems with windshields spontaneously cracking.
Second of all, windshields are a major safety part. 4 to 8 months is way too long for any part, let alone the windshield. Honda has tons of them on hand because they are still building 10th Gen Accords.
It seems like your dealer (or whomever) is BS'ing you. The dealer should be able to get one in a couple of days. I'd check with another dealer or contact the Honda corporate office if the car is still under warranty.