"But it's irrelevant."
how on earth is it irrelevant? It doesn't matter if I'm buying a $10 watch at Walmart. If it has resale _value_, that is something that will and should affect the initial 'price that the market will bear' for the good.
Things have value. Houses have value in the fact that they are still good for their intended purpose after many years of use. When you move, you sell them instead of abandoning them because they still have value, and you can trade on that value. The 'price the market will bear' for your house is based on it's value to the market.
A used car has value in proportion to its features and how much useful life it still has. It wears down over the years, and by the time mileage reaches 100k it has significantly less value than it did at 20k. But value has not reached zero, hence I can find someone to buy it for a few thousand dollars because to them, it has value worth paying for.
If publishers are insisting that people throw away the value left in the good that they would normally resell, then the prices better come down to reflect that loss of value in the product.
Cars and houses have high prices because of the value present in the resale market. The fact that there is Value left in the items is the cause, the prices are not. The used game market being what it is shows that there is still value in used games, just as there is in used books, electronics, cars, houses, etc.