Thank you for having a discussion like this here @petertodd. You have a lot of experience and contextual insight you bring.

I think that most people would agree that the bitcoin protocol needs to, ad infinitum, provide incentive to contribute work to the network.

As a first step towards that, one way to ensure that there is always a non-zero block reward, while retaining the property of finite total supply, would be to:

Are there particular economic reasons why you would consider the above not a viable path, or at least a natural step in the right direction?

This continuation of the subsidy halving schedule seems more "natural" in that it does not arbitrarily pick some target inflation tax or demurrage tax and add it to the protocol. Rather, it simply continues the existing inflation tax which is passively and pro-rata paid by all utxos.

Ultimately I suppose one way we could look at the block subsidy, not just tail emmission, but any subsidy at all, is that it is a technically "simple" way for all utxos to passively, and pro-rata pay for block creation.   Yet, when we transition to a post-subsidy (and hope there is a robust fee market by then!), it also means it is also a transition to only some utxos actively paying for block creation (via fees). So we have a freerider problem. And it is ironic, because the freeriders in the post-subsidy scenario are the hodlers, yet the hodlers are a large part of why bitcoin works at all!