Bitcoin's mining centralization problem (Hashrate ≠ Freedom) - TL;DR

Hash power is coordinated by a small number of mining pools. At times, the top 2-3 pools reach or exceed 51%.

These pools decide which transactions go into blocks by setting templates and policies — including filters and OFAC (Office of Foreign Assets Control) lists.

Individual miners chasing predictable payouts delegate that power upstream.

As a result, a regulator only needs to influence a few pool operators, not thousands of ASIC owners.