Perhaps true, but there's more to life than money. The basic formula for work enjoyment is autonomy, mastery and purpose (the intrinsic motivators) and those are often much more attainable at a startup. Money and fame are extrinsic motivators that many find ring hollow after a while and they notice they don't enjoy waking up and going into the office each morning.

Everyone's situation is different so try not to assert that any choice is incorrect based on a single, somewhat vacuous metric.