I'm constantly amazed at people interpreting facts differently.
There is no 'legislation' as such sending black power into obscurity. There is regulation of certain chemical compounds (black powder being one) by the BATFE, which is a federal bureaucracy. Yes, I'm splitting hairs with the language, but I thought the facts should be stated correctly at least once.
The classification of black powder by the BATFE is based on it's chemical composition, which is greatly different than smokeless powder as we all know. BATFE says the chemical composition of black powder is easier to detonate than that of smokeless powder, thus the difference in classification (how fast it burns has nothing to do with the difference). There is evidence for that finding, despite the fact that many of us think otherwise.
So, regardless of the opinion of the expert at Graf's, the federal government is certainly involved in the availability of black powder at retail. It's their finding and regulation that results in the classification used by the retailers, shippers and insurance companies to determine how they must treat the substance and thus how much cost is involved.
The state governments are also involved in creating cost burdening regulations. There are storage regulations for explosives that are used in construction, and because of it's explosive classification the storage of black powder is affected.
Most local retailers, and all of the big box sporting goods retailers, have decided to just not address the issues created by the explosive classification of black powder, and thus it's not readily available over the counter. A few continue to sell it but pass the costs along in their pricing, as you would expect. As to whether or not they, and the insurance companies, are 'taking advantage' of the opportunity, well, that's a matter of opinion that I won't address.
The mail order companies, (Graf, Powder Inc., etc) do offer a viable alternative if one does not want to go to substitute black powders. Small lots (25 lbs or less) will keep you from running afoul of the regulations almost everywhere, although it's wise to check with state authorities before committing funds.
Are the substitutes that much better than real black? While there are as many opinions about the substitutes as there are people, I doubt anyone would claim they are 'much' better. They have their good points and their bad points. I personally like and use 777, but there are plenty of people who will, with good evidence and reason, disagree with me. I prefer to use real black powder, but 777 is 'good enough' to use when I want to preserve what stock of real black I have left. That's my position.