People have every right to voice their opinion, it all comes down to a matter of what we want and how much we are willing to pay for it. There are people who will pay a lot of money for a tarted up SUV, when in reality it is basically a pickup truck costing half as much underneath. People buy expensive makes of cars because they feel like they are 'value', while I could make some logical arguments they are way overpriced, given what they give you *shrug*. I paid 450 bucks for a Williams Brass engine that was produced 20 years ago +, and I consider it a bargain,which sounds kind of dicey for something that is 20 years old, but I wanted one *shrug*.
I suspect what you see is a combination of higher costs, for raw materials and also as contracts get renegotiated, the factories charging more, and their own internal costs, and also Lionel looking at their market and trying to maximize their profits, by tinkering with supply and prices versus demand. What companies do is try and figure out the 'sweet spot' where they make the most money, which ideally limits how many they have to sell to reach it. A lot of items are of low volume or BTO, and they set their price point on the assumption they will get enough orders to reach their sweet spot. If they don't have enough demand, they cancel it. As others have pointed out, they know there are people who will pay the price, who want the units, and in effect that is what they target with their pricing model. If they know (or think they know) that if they make 100 of a particular item, they can make let's say 50 bucks profit @ price (keep in mind this is based on the wholesale price, Lionel doesn't care about the retail), so they would make 5k profit. If they think 100 people will pay the cost of that at that price point, they would rather make the 100 and sell them, rather than make 500 at 10 bucks profit at a lower price, in large part because even at the lower price, they may not sell 500 and be left with remainder.
Part of this might be them looking at the economic news, and figuring (wrongly or rightly I I can't say), that jobs are picking up, wages are slowly starting to pick up, so they may feel free to raise prices more, assuming that people will be more willing to pay them if in fact the economy is getting better. In an economic downturn prices tend to be suppressed, if the economy improves prices often go up.
Are the trains worth those prices? I can't say, that all depends what you are looking for, and while I sympathize with those saying basically the same engine that cost 400 dollars last year is now over 500 sounds fishy, that it doesn't seem to be much of a value add, in the end it depends on how much people value the item. People often buy cars at auction that you scratch your head at, the price seeming to be way out of whack, but you find out the guy loves the kind of car, fell in love, and paid what he wanted.
The only way this is gonna change is if Lionel finds that their new pricing causes less demand than they expected, in which case they can certainly cancel production of a BTO run, but they can't do that too often, since a canceled production run still has costs behind it (they have to build prototypes, for example, have people design them, figure out parts, etc), so a canceled BTO is not only no sales, it is also a loss. The other option is to see if they lower the price, if demand goes up enough to make their point, and that is an unknown, too, how many people would buy the engine at 400 instead of 500. I suspect to be honest that more than a few of those complaining about the price increases wouldn't buy them at the old prices, either.