I have to agree with your suggestion of subscribing to a database rather than buying documents one off. This creates a much more sustainable business model for these organizations by ensuring that subscribers will always have access to these articles and the subscriber will continue to pay an annual fee. In theory this should fund future work on these standards but the reality is they run the risk of an individual or company signing up, taking the information needed and then cancelling the subscription. It may be something worth discovering but I for one, would most likely be in the latter camp which might be an indicator as to why the don’t offer these services.
-Tarek