The global rise in thyroid cancer incidence over recent decades is largely attributed to increased detection of papillary thyroid microcarcinomas (PTMCs; ≤1 cm) from widespread ultrasonography and ultrasonography-guided fine-needle aspiration. Meanwhile, the associated mortality has remained stable or declined, suggesting significant overdiagnosis. Autopsy studies consistently report incidental differentiated thyroid cancer in 4–36% of individuals, with prevalence up to 36% in thorough whole-gland examinations, indicating that many small papillary carcinomas are indolent and clinically insignificant during a patient’s lifetime. This review synthesizes evidence from autopsy findings, epidemiological trends, and long-term observational studies to evaluate how screening and diagnostic intensity contribute to rising thyroid cancer diagnoses. We compare recommendations from the 2015 and 2025 American Thyroid Association guidelines, the 2022 National Health Commission of the People’s Republic of China guidelines, and the Bethesda System for Reporting Thyroid Cytopathology, with attention to active surveillance, de-escalated surgery, reduced radioactive iodine use, and minimally invasive techniques (e.g., radiofrequency ablation) for appropriately selected low-risk PTMCs. Remaining areas of debate, including the management of lymph node metastases, the interpretation of recurrence risk, the utility and limitations of thyroglobulin monitoring in conservative management settings, and the enhanced accuracy of molecular testing, were also discussed. The analysis supports the value of refined risk stratification and patient-centered decision-making to reduce overtreatment and its associated morbidity while maintaining vigilance for the minority of cases with more aggressive behavior.