Retailers and consumer brands in the USA and EU are reframing merchandising around Generative AI (GenAI). Three capability stacks are scaling fastest: (1) personalized storytelling (AI-authored product narratives and shoppable content), (2) dynamic content/creative (DCO for ads, dynamic product ads, on‑site modules, email, and CTV), and (3) micro‑influencer campaigns orchestrated with AI for creator matching, briefing, and asset remixing. Anchored by robust AI‑in‑retail growth forecasts and broad enterprise AI adoption, we model AI‑in‑merchandising sub‑segment spend in USA+EU rising from ~US$7.0B in 2025 to ~US$20.5B by 2030. Adoption is propelled by first‑party data mandates, creative production cost deflation, and measurable uplifts in engagement and conversion tempered by governance needs under the EU AI Act and brand‑safety controls. Operationally, GenAI compresses content cycles from weeks to days, enabling seasonal, local, and persona‑level variants at scale while keeping visual and voice consistency within brand guardrails. Personalized stories improve product discovery and AOV in categories with complex attributes (beauty, electronics, home). Dynamic content engines re‑rank products and render creatives on‑the‑fly across ad, email, and owned surfaces.