I mean IDK. Flight cancellations happen a lot.
I'd expect Disney to be accommodating to a hurricane (which they were) that is happening in their backyard but a flight cancellation that happens to thousands of people everyday?
I don't think it hurts to ask in most cases but don't go in expecting them to give you a break on a ticket price, or bridge it. They have a policy in place for a reason and any exceptions should always stay exceptions not the norm, not expectations.
Like I said though the OP chose to go to the parks. They could have gone mini-golfing, resort hopping, gone to Disney Springs, etc any number of things. They opted to add in more park time.