When can we start pruning old spent utxos with our full nodes?

Cash fusion is never going to be permanently untraceable. Neither is XMR. Zcash..... fuck it, it could be a honeytrap. It's always a race against time. The only way I can see us winning is to start pruning those old spent uxto's. Then it's a race the government can hardly win, as we will continue to refine BCH cash fusion and XMR.

How realistic is this? Are people working on this? Should this be our biggest priority?

Also, let's talk about the issues. Sometimes you need to prove a transaction happened. Sometimes institutions need detailed records. So what should be the policy? I think if a utxo is spent, and then spent again, >2 years ago, it should be pruned from all full nodes, if possible.