If one day these "dead UTXOs" become a burden on the network, might the Bitcoin protocol need its own mechanism to delete or even destroy old UTXOs?
This goes against Bitcoin ethos on immutability and property right hence the major pullback on the quantum resistant proposal.
UTXOs continue to grow over time, some even remaining untouched for years.
The growing size is something that we have to face in the future and ordinals had a hand in pushing it
But Node pruning which reduces blockchain storage though not UTXO set size can help mitigate the increase in size downloaded by full nodes.
Or could the existence of these "ghost UTXOs" hold the key to creating a new kind of privacy
They could but I believe Taproot are more practical.