Sure, that would be another reasonable thing the Bitcoin community might do to allow some folks to not spend but also not have their coins burned. It still leaves someone who forgot about their Bitcoin with it burned even though their next-of-kin might have found it. There’s always a burn risk, just a question of whether the future Bitcoin community will decide they’d rather do that or not.

Sure. But I'd still push back on the theft analogy. Burning coins is never theft but a quantum attack sure would be theft. So by burning coins we strictly reduce theft.