The title is wrong. It’s not about proving that the owner is dead (which is easy, you get a death certificate when a relative dies).
It’s about proving that the person requesting access of the dead person account is actually the person legally receiving the dead person’s possessions (or GOG account specifically).
The discount cycle is on purpose. First you bank with the impatient whales who will buy not even the full version at $70 but the deluxe version with useless cosmetics at $100+.
Then after some times has passed, you do a sale at $45 so people who are willing to pay just this price buy it.
Then lower again, and again until all potential customers have bought the game at the maximum they’re willing to.
The problem is that the Steam Deck plays PC games, that were designed for a big screen. You can’t make the screen much smaller than the current Deck while keeping it legible.