Many people think that Bitcoin's supply cap—21 million coins—won't be fully mined until 2140, so this is a distant problem that doesn't need to be worried about.

But the reality is that the pressures on Bitcoin's security and economic model will not wait until that day; they will emerge much earlier.

Where does the miner's motivation come from?

Currently, Bitcoin miners' main income comes from two parts: block rewards and transaction fees.

They have to pay huge costs in hash power and electricity—about 1.8 million kilowatt-hours of electricity is needed to mine one block, which, at $0.05 per kilowatt-hour, costs $92,000 just for electricity.

The reason miners are willing to invest is that the block rewards are substantial:

Currently, the reward for each block is 3.125 BTC

At current prices, this part of the value is approximately $370,000

Plus about $25,000 in transaction fees, total revenue is approximately$395,000

With such economic incentives, miners have the motivation to maintain network security.

Reward halving: the countdown has already begun

The Bitcoin protocol has a hardcoded rule: block rewards are halved every four years.

By 2032, the reward for a single block will drop below 1 BTC

By 2040, 99% of Bitcoin will be mined out

Ultimately, block rewards will reach zero

By then, miners will have to rely solely on transaction fees for survival. The problem is that currently, fees account for only about 7% of miner income, far from covering costs, let alone making a profit.

To allow miners to continue operating, fees need to increase at least 4 times to cover electricity costs. Considering hardware depreciation, operational risks, and profits, a growth of 6-10 times may be needed. This means that the future Bitcoin network requires continuous and high-value transaction activity to maintain security.

Limitations of block space

Some may ask: 'As demand grows, won't transaction fees rise?'