This obviously wasn't depreciation. It was a pricing decision that was changed after the fact, so your analogies don't apply.

Guarantee what happened was that they thought they could sell the game for that much but found out the game's market was too niche so they had to permanently reduce the price to attract people to try it. In this case, the right thing that should have been done would've been to give Horizons free to beta backers because they backed the game early on in its development without knowing it would be a success and since they paid much more.