From other article:

A study by Junhyuk Lee (Texas A&M University), published in June 2026 under the title Bitcoin After Block Rewards, proposes a theoretical framework for analyzing Bitcoin’s security in a system where the block reward gradually decreases and miners become increasingly dependent on transaction fees. The goal is not to limit the analysis to the distant year of 2140, but to study the transition during which the economic incentives for mining change in nature as the block reward becomes secondary.

The model introduces a deviation threshold beyond which it becomes rational for a miner to deviate from honest behavior. Security is thus treated as an endogenous variable, depending on the structure of mining revenues and their evolution. A central point of the analysis concerns the adjustment of mining costs: miners enter and exit the market based on their profitability, the difficulty adjusts, and the system tends toward an equilibrium where the marginal cost aligns with revenues. However, this mining equilibrium does not automatically guarantee the stability of overall security, as the cost of a 51% attack can change independently of the profitability of the remaining miners.

The study shows that under the current system, the block subsidy remains sufficient to maintain incentive alignment. However, in a future fee-based system, a structural revenue shortfall could make deviant strategies rational, even if the system appears to remain in economic equilibrium.

When the rise in the price of Bitcoin is insufficient to offset the decline in the block subsidy, the author does not conclude that the protocol automatically fails, but proposes several corrective mechanisms. In particular, he examines the introduction of a fee floor, the implementation of a fixed component such as a base fee, and dynamic adjustments to block size. These measures, which obviously do not affect the 21-million cap, aim to boost revenue per block and push back the threshold at which miners’ incentives become unstable.

The study therefore does not predict a breakdown of the system, but highlights a gradual transition in which security increasingly depends on the fee market’s ability to take over from the subsidy, and in which protocol adjustments may become necessary if Bitcoin’s market value proves insufficient.