Next.js suffered a 10 percentage-point CWV drop when FID was replaced by INP (March 2024) — "modern stack" is not synonymous with "fast"

Claim: Per the 2024 Web Almanac Performance chapter, Fig. 9.3: "Several technologies were significantly impacted, including a 19% drop for 1C-Bitrix, a 10% drop for Next.js (a React-based framework), and an 8% drop for Emotion (a CSS-in-JS tool)."

Confidence: Verified.

Implication: "modern stack" is not synonymous with "fast." Client-side React without disciplined SSR/SSG is one of the few cohorts moving the wrong direction on Core Web Vitals.

For Candid: when arguing for Astro over Next.js for marketing sites, this is the cleanest framework-level data point. Astro's 2023 Web Framework Performance Report had Astro as the only framework exceeding 50% CWV pass — see Astro vs Next.js (eastondev benchmark, Dec 2025): ~40% faster, ~90% less JS for static content (existing). Next.js sat at the bottom of the pack with ~1-in-4 pass rates.