In the software development landscape of 2026, the "failure rate" of the pure Waterfall model remains significantly higher than Agile or Hybrid methodologies. Historical and modern data suggests that approximately 59% of Waterfall projects are considered failures, meaning they were either cancelled, significantly over budget, or failed to meet the initial requirements. Only about 13% to 15% are consistently rated as "successful." The primary reason for this high failure rate is Waterfall's inflexibility; because testing and feedback occur only at the very end of a multi-month or multi-year cycle, any misunderstanding of the initial requirements can lead to a product that is obsolete or non-functional by the time it is delivered. In 2026, while Waterfall is still used for highly regulated hardware-integrated projects (like aerospace or civil engineering) where requirements are set in stone, most software firms have moved away from it to avoid the "all-or-nothing" risk associated with its linear structure.