As I said before, Amtrak practices yield management and it makes no sense from a yield management standpoint to sell your inventory at a low price early on when your projection of demand is fuzzy and so block that inventory from sale at higher price point later as demand develops. You allocate inventory to lower buckets when you have a clearer picture of demand. That is how yield management is done, you will find airfares, for example, are generally pretty high 11 months in advance, too.
Prizes are not awarded for early booking as they once were before Amtrak's yield management practices improved.
Sleeper accommodations are a scarce commodity with high demand. A fair price is what a willing seller and willing buyer agree on. A price that someone is willing to press the purchase button on is, by definition, not insane.
I will not pay more than the lower buckets myself. That is my choice. I play the game and am usually able to play it well enough to get low/lower, typically in the 5 month out range. I will refuse pay $1500, the new top bucket for a roomette on the Builder, but I also do not feel I am entitled to get one at $588, either because I do not like or cannot afford $1500. No one has to ride in a sleeper to get to where they need to go and a better fare is usually obtainable with some patience, work and flexibility anyway.
Personally, I like VIA's system with stable seasonally based fares, but I also think it makes less economic sense than yield management. I have no quarrel with yield management as long as it is done right, with few rooms going out empty. If everything was always booked, it indicates pricing is too low. If a lot are empty, pricing is too high. In either case, money is being left on the table.
This is Econ 101. The iron laws of supply and demand in action. There are ways to ration scarce commodities other than price, all of them less equitable.