the most recently 'removed' opcode is OP_CHECKMULTISIG; it's available in pre-segwit and segwit v0 scripts.
it's not available for segwit v1 scripts (aka taproot scripts or tapscript)
Ah, but this would mean that you are relying on people moving coins to a new address type?
If that's the case, it's pretty clear why it's unfeasible, it took forever for people to adopt segwit, and it's taking forever more for people to start using taproot.
If that's the case, it's pretty clear why it's unfeasible, it took forever for people to adopt segwit, and it's taking forever more for people to start using taproot.