I'm happy you say this, and I wish it was more well known, even if obvious. People join early-stage startups for the potential bucks. I'm not saying that's a good reason, but I'm saying most graduates, who are not as educated about the world, will join a startup for the money upside. Being honest like you are is not the same as admitting there is some degree of deception in the culture about how well off you'll be as an early employee in the startup world.