100K is not more than enough to live on, if you live in the Valley and have a family (say 3 kids) then 100K barely buys you a comfortable lifestyle. I know that is not the point of this thread but so much focus of these discussions seems to pivot around a 22 year old college dropout who lives with roommates in a shared apartment.
When you reach a certain point, say your mid-30s and you have kids your financial obligations can extend far beyond what people think is necessary to 'live on'. You have retirement contributions, savings for college, long term care for family (most people believe it or not, have to help their parents out at some point).