I see coins aging could be a viable on-chain scaling solution (scenario where coins that was not been moved for full halving period will automatically return to coinbase). If this will be the case - full nodes will only require to store blockchain for the past halving period since anything that remained unspent will transfer to the coinbase. This is drastic and, perhaps, cruel measure to take but that will also solve satoshi't billions, burned and lost coins problem.
Firstly, not everyone sees that as a problem and I think you would struggle to find consensus for stealing peoples' property just because you believe they aren't using it when it's been there for a while. And secondly, the very act of moving idle coins around and reintroducing them into circulation would result in more transactions, which places more burden on the network. I have coins I haven't moved in four years and they're not going anywhere, thank you. This sounds very much like altcoin territory as it likely decimates Bitcoin's predictable supply ethos when "new" money would come flooding back into the economy every halving.
Not to mention the miners that grabbed the first block after that got approved could completely fuck the economy if the coinbase reward included Satoshi's stash along with all the other coins presumed lost. It would literally be the biggest block reward since crypto was invented. Potentially worth trillions of dollars depending on what the price is at the time. Those miners would be newly anointed Gods on Earth and everyone would lose confidence as it all comes crashing down. Think it through to conclusion, please.