According to Billy Boone from Simple Mining, even after the block rewards end around 2140, Bitcoin miners will still be crucial for network security. He emphasized that the total block reward consists of two parts: the block subsidy and transaction fees. As the block subsidy decreases, miners will increasingly rely on the transaction fees driven by the scarcity at the protocol level of Bitcoin: that is, the limited space available for transactions in each block. Boone compares miners to settlement providers who prioritize transactions during peak block space demand periods to earn fees, similar to traditional payment processors.