That doesn't mean extreme frugality is the first thing people should focus on though. People have limited willpower. Using it to cut out $20/week worth of lattes or $100/month worth of cable just isn't the best use of it, unless you've already covered the more important things. As I've tried to illustrate above, focusing on the wrong things (and failing), can be very counter-productive. Personally, I think your limited willpower is almost always better spent adding to or honing the skills that will allow you to produce more.
In other words, maybe the 'limited' part is artificial and can be changed. And maybe strengthening our willpower would benefit us beyond just denying ourselves arbitrary comforts. Such as, willpower to pursue adding to or honing skills, maybe even ones that don't reap immediate material benefit.
So, cutting out lattes may make you better able to improve as an entrepreneur, or programmer, or whatever.
Relaxation: I work better during the week if I've had a relaxed weekend. Working better leads to a greater likelihood of promotion and thus more income. Also I'm more likely to job hunt if I feel confident about myself. That positive psyche comes from positive environment and often that means having relaxation time at home.
Consumerism: The very reason I got my first job was because I wanted to buy a Dreamcast. When I wanted a house, I changed to a better paid job. Then I wanted nicer things for my house and a car, so I asked for a pay rise. Sometimes greed can be a positive force (if channelled appropriately).