The most dangerous question in Bitcoin isn’t about scaling. It’s about the last coin.
This week, a talk from 2024 resurfaced. Peter Todd, a long-time Bitcoin core developer, stood on a stage at Bitcoin++ and argued that the 21 million cap is a security liability. His proposal: a permanent, tiny block reward – a tail emission – that never stops. Miners would always get fresh coins, even after 2140. The chain would stay secure. The cap would be broken.
Adam Back, the cypherpunk who helped invent Bitcoin, fired back within hours. He called it a “trap dressed up as engineering.” He compared the campaign to BIP-110, a failed soft fork that tried to filter non-payment data out of blocks – a fork that died after two blocks with only 2.53% miner support.
Two of the sharpest minds in Bitcoin, on opposite sides of a line that hasn’t been crossed in 17 years. The ledger remembers every trembling hand that touched that line.
Context: The Security Budget Paradox
Bitcoin pays miners in two ways. Block subsidies mint new coins – currently 3.125 BTC per block. Transaction fees ride along with each block. The subsidy halves every 210,000 blocks, roughly every four years. By 2140, the subsidy hits zero. After that, fees alone must secure the entire network.
The problem is that fees are a terrible salary. They spike during mania – think 2021 when a single transaction cost $60 – and crash during bear markets. In 2023, fees averaged less than $1 per transaction. In 2025, Ordinals drove fees above $20 for weeks. Then they dropped back to $2. This volatility is baked into the protocol.
Todd’s argument is simple: if miners rely only on fees, they will have an incentive to reorganize the chain and re-mine blocks that contain fat-fee transactions. They could steal the fees from honest miners. The chain becomes a game of “which block gets the fees?” instead of “which chain is longest?”. A tail emission, even 0.1 BTC per block, kills that incentive. It creates a fixed baseline that miners can count on.
Core: The Forensic Case for Tail Emission
Todd’s case leans on mathematics. He models Bitcoin’s supply against a loss rate – coins that are lost forever through forgotten keys, hardware failures, or death. He finds that under a fixed supply, the circulating supply eventually reaches a ceiling because coins vanish as fast as fresh ones appear. The real inflation rate approaches zero. Monero already runs a small permanent reward, and its apparent inflation rate keeps sliding toward zero.
The timing matters less than the mechanism. We are close to 30 more halvings. Each one thins the subsidy further while fees stay lumpy and unpredictable. I’ve built AI trading signals that cross-reference on-chain fee data with social sentiment. The patterns are clear: fees are not a stable income stream. They are a chaotic signal that miners cannot budget against.
During the Terra collapse, I spent three months tracing on-chain flows between Anchor Protocol and UST. I saw what happens when an incentive structure breaks. The logic chains broke where greed connected. Miners would face the same collapse if fee revenue drops below the cost of electricity. A tail emission is not inflation – it’s a stabilizer.
But there is a deeper problem. Todd’s argument assumes that fees will remain low. What if fees grow with adoption? In a world where Bitcoin processes millions of transactions per day, fees could be substantial. The Lightning Network already handles thousands of payments per second. If fees become the primary revenue, miners might be fine. But we are not there yet – and we won’t know until 2140.
Contrarian: The Trap
Adam Back rejects the framing outright. He points to BIP-110, the 2026 soft fork that tried to filter non-payment data out of blocks. The campaign was sold with simple narratives: “JPEG spam and illegal content could be stopped” and “anti-layer2 anchors want to Ethereumize Bitcoin.” The fork failed. Back had predicted the stall weeks earlier.
Back sees the supply-cap debate as the same pattern. “The trick is finding ways to trigger and rally people to your dangerously inadvisable cause with simple though false narratives,” he wrote on X.
One difference cuts against Todd. BIP-110 asked for a soft fork, which needs only miner cooperation. Raising the cap demands a hard fork. Every holder would have to accept it. Nodes would have to change their consensus rules. Exchanges, wallets, and layer-2s would have to upgrade. The coordination cost is enormous.
Silence is the only honest metadata here. The Bitcoin community has not rallied around Todd’s idea. The fact that the talk resurfaced three years later is not a sign of momentum – it’s a sign of stagnation. The debate is a ghost that haunts every Bitcoin conference, but no one is willing to fork over it.
Takeaway: The Next 100 Years
The 21 million cap is a social contract, not a mathematical law. It is the most sacred rule in Bitcoin. Breaking it requires a consensus that does not exist. The debate will simmer until 2140 gets closer, or until a fee crisis forces the issue.
But the security question survives the politics. Fees may yet fund the chain on their own. Nobody alive today will see that test settled.
The ledger remembers every trembling hand that touched the supply cap. And the ledger does not forgive.
Speed wins the trade, clarity wins the war. The trade is to stay neutral on the cap. The war is to keep Bitcoin secure. Both sides agree on the war. They disagree on the battle plan.
Will the cap ever break? Not in my lifetime. Not in the next 50 years. But the debate is healthy. It forces us to think about the long term. And that is exactly what Bitcoin needs.