The Problem with Huge Lists

Rendering 10,000 rows creates 10,000+ DOM nodes. The first render is slow, memory grows, and scrolling and typing lag. The user only ever sees about 10–20 rows at a time.

Without virtualization:  10,000 items  →  10,000 DOM rows
With virtualization:     10,000 items  →  ~15 DOM rows (only the visible ones)