&gt;At present, all notable proof-of-work currencies reward miners with both a block reward, and transaction fees. With most currencies (including Bitcoin) phasing out block rewards over time. However in no currency have transaction fees consistently been more than 5% to 10% of the total mining reward[^fee-in-reward], with the exception of Ethereum, from June 2020 to Aug 2021. To date no proof-of-work currency has ever operated solely on transaction fees[^pow-tweet], and academic analysis has found that in this condition block generation is unstable.[^instability-without-block-reward] To paraphrase Andrew Poelstra, it's a scary phase change that no other coin has gone through.[^apoelstra-quote]<div><br /></div><div><br /></div><div><br /></div>We should consider that a fixed block reward doesn't guarantee that the value of energy securing transactions is greater than the value being transacted in a practical amount of blocks where practical is a certain amount of time (currently 1 hour). If the energy expenditure is less than the value transacted in a given amount of blocks those transactions are at risk of being double spent. We have seen this failure with Ethereum Classic where any meaningful amount of value would need 2 weeks of blocks to be deeply confirmed for economic purposes. <div><br /></div><div><br /></div>We should also not assume that the Bitcoin emission curve implies there will be zero block rewards for mining Bitcoin, let me explain. There's an ugly solution that doesn't require a hard fork (I'm not advocating for this solution just presenting it) where a new coin is launched to merge mine with Bitcoin and that new coin (called BTail for discussion purposes) would enfranchise everyone who is a Bitcoin UTXO holder at the moment of the real-time launch of BTail at a well known block height. Using a technique we have seen with BCH to create an arguably fair launch. BTail would have a floating exchange rate to Bitcoin and its success or failure in terms of adoption would be determined by the market. It would require the same network effect barriers as a hard fork (opt-in) but would not put Bitcoin at risk while people can take time to install new software (and write new integrations) as they would with a soft fork. <div><br /></div><div><br /></div>Regards <div><br /></div>Peter Kroll <div><br /></div><div><br /></div><div><br /></div>