You're equating contract terms with general reciprocity. Many, perhaps most other businesses pro-rate subscription services and understand that customers may need to cancel, if only because they don't want the sort of bad publicity Adobe is receiving right now. Tough contracts with significant breaching penalties are generally made between peers (two individuals or two businesses) rather than producers and consumers.

There is a doctrine of unconscionability in contract law that says just because you secure agreement to highly unfavorable terms doesn't mean the contract is beyond review of a court, if there is a significant asymmetry between the contract parties.