We kind of have that now with ranchorelaxo, he lost his keys and Haejin only has the posting keys and unfortunately 300K HP delegation. All the curation rewards earned on Rancho are likely lost for good. Unfortunately this doesn't get reflected anywhere.

The "burning" being done imo does nothing, no one cares or really looks at supply to make decisions. I've always said, I can burn my entire stake (~3M Hive) and the price won't move one cent. That being said, removing Hive/HBD from circulation does reduce sell pressure, and that for sure affects the price.