The coins are spendable. They are in your node's utxo database and the protocol allows them to be spent. Feature, not bug.
Therefore:
They can be spent. Assuming anything else is self-deceit, unless you are Satoshi and you know you lost the keys.
Any attempt from any developer to make these coins unspendable is a breach of protocol.
The owner of the keys to these coins can burn the coins if they don't want them: OP_RETURN will make them unspendable.
If you believe these things to be true, then if or when the time comes where we are faced with some sets of devs finding themselves VitaLARPing into benevolent dictatorships, your resolve shall be tested.
OP_RETURNwill make them unspendable.