The extreme rarity of magnitude 10+ earthquakes underpins the 99.2% market-implied probability of "No" before 2027. USGS records show the largest event since 1900 reached only 9.5 in Chile's 1960 Valdivia quake, with subsequent great events like the 9.2 Alaska 1964 and 9.1 Tohoku 2011 quakes confirming a practical upper limit tied to Earth's crustal thickness, subduction zone lengths, and maximum fault slip. Generating a 10.0 would require rupturing roughly 14,000 km of fault with extreme average displacement, far exceeding observed tectonic settings. With just months remaining until 2027, recent global seismicity monitored by the USGS shows no trend toward such extremes. A realistic shift would demand either an unprecedented multi-segment rupture or revised magnitude scaling models, both considered highly improbable by current geophysical understanding.