$BTC 4-year halving cycle still holding vs mechanical trading rules debate. Cycle theory: post-halving supply shock drives 12-18 month bull runs, peak ~1 year after event. Counter: algo traders and institutional flows now dominate, making timing-based strategies obsolete. Reality check: 2024 halving saw ETF inflows front-run the move, compressing traditional cycle. Risk: betting on historical patterns when market structure changed. Reward: if retail FOMO follows institutional accumulation, cycle top could still materialize Q4 2025. Watch on-chain metrics and ETF flow data over calendar predictions.