Bitcoin mining difficulty surged 34% since the 2024 halving, reducing per-unit output and squeezing margins as energy costs rise. Trend data indicates that older rigs (e.g., S19 models) are nearing shutdown prices (~$54,000-$65,000/BTC) at 6-7 cents/kWh. Investment returns are increasingly tied to advanced ASICs, which are 50 million times more efficient than 2009 hardware. Miners upgrading equipment and relocating to low-cost energy hubs (e.g., Texas, Asia) may maintain positive returns, but high upfront costs and regulatory risks (e.g., U.S. EIA surveys) limit prospects for smaller players.