This is a loaded question with heavy hindsight bias.
You don’t decline a “well known company before it was well known”. At the time, you’re declining an unknown company. Unknown companies are inherently riskier than established companies. Established companies are almost always messier, less organized, and less impressive when they were young.
The funding environment has also changed substantially over the last decade. In the past, working for an unknown startup didn’t automatically mean market rate salary plus lucrative options. It was common for startups to pay people a lot less than big companies because they just didn’t have the money.