You are confusing technology for product. The product space they entered, UX design tooling, was very crowded. Sketch and InVision were the kings and there wer

You are confusing technology for product. The product space they entered, UX design tooling, was very crowded. Sketch and InVision were the kings and there were a dozen other reasonable options to choose from (including ones in browser with real time collab and other interesting tech). Figma entered that market later and won on a combination of technology and product innovation aka execution. But they absolutely entered a crowded market.