How does Bitcoin keep block production at a roughly steady rate as mining hardware gets faster?

Difficulty is set by a moving average targeting a fixed number of blocks per hour — if blocks are coming too fast, the required work automatically goes up.

More and faster miners would otherwise produce blocks quicker and quicker. To prevent that, the network periodically retargets the number of leading zero bits required, holding the average block interval roughly constant (about 10 minutes in Bitcoin).

This decouples both the coin-issuance schedule and the network's security from raw hardware speed — the chain advances at human timescales no matter how much mining power joins.

Concretely, Bitcoin retargets every 2016 blocks (about two weeks): it measures how long that batch actually took and scales the difficulty up or down to steer the next batch back toward the 10-minutes-per-block goal. Faster hardware just pushes the difficulty higher; the interval holds.

Go deeper:

• Difficulty — Bitcoin Wiki — the 2016-block retargeting formula that keeps the average block interval near 10 minutes as hash power rises and falls.