Consulting is a job. You have one or a couple clients, and you only have to satisfy them to get paid. You can work during the day, relax at night, take vacations, and generally let work come to you, since there is massive demand beyond supply for your services. A startup is your whole life. Your job isn't just to satisfy a couple focused business people, but generally thousands or millions of fickle consumers. There…
The average person could sustain themselves on very little income, and yet most jobs pay far beyond than that amount.
Everyone wants nice, nonessential things, and so they want salaries beyond what they "need." It's a standard for people to get paid way beyond what they need so that they can go blow it on thing they don't need.