About 2 years ago I caught something on TV... I don't remember the name, but it was something about UA flights. They were showing this flight and saying how much revenue it had (they even said how many non-revs were flying, including pax on award tix), what the costs were, how much money it made, etc. They also had an interview with some UA executive explaining various things. The person interviewing asked if seats that were bought with miles were seats they weren't expecting to sell anyway and the guy danced around the question, sort of hinting towards a positive answer.

Remember that award inventory is capacity controlled. If they expect to fully sell a flight, no seats are made available for awards. That is why it is very difficult to find awards at peak travel times (e.g. around certain holidays). Airlines don't sell 100% of the seats on 100% of the flights. There will always be some empty seats. The revenue management software, when it does the pricing and everything, also computes how many seats are expected to go unsold. I am assuming that at least some of those seats are made available for awards; it would be a win-win situation for the airline.

Now think of airlines and FF partnerships. If 2 airlines are partners, it makes sense for them to share award inventory. I.e. all award seats are available to members of both FF programs. Why would they bother paying each other? It sounds like a complicated, unnecessary exchange. Those seats would be empty anyway. Why keep swapping around small amounts of money, when it will likely pretty much even out in the end?

Even if airlines do pay each other for awards, if the seats are there available for redemption, when making a reservation the computer has to know the cost in miles in order to complete the ticketing. The information is there and no, it doesn't change all the time (the agent lied to RealHJ). Except for the secretive hike in intra-Asia awards, awards have pretty much stayed the same. They keep the chart hidden from us for a reason; this is a well thought-out decision. I have serious doubts they're keeping that information hidden from us for our own good, like to surprise us with lower requirements than we expected. Oh no, there is definitely evil behind this; that's why they continue to lie to cover it up.