Can you elaborate on this question? Are you asking whether people who work 40 hours per week would take a 90% pay cut to work 90% fewer hours, or are you asking a different question?
Assuming that you're referring to working x% of full-time for x% of the money, then yes. I could easily live off $300 per week, but even minimal wage gives me NZ$500 per week. A well-paying job should give me about $1000 per week. Under those conditions, I'd choose a 12-hour work week in an instant.
However, you refer to a 4-hour work week. That's not a lot of time. Assuming that I'll still make at least $300 dollars per week, then yes. Any less, probably not. I still have to eat.
I think the real underlying question is about time-money tradeoff.
As for a 4-hour work week, there's a sense in which a work week that is too short will bore you to death. I would take a pay cut in exchange for, say, 30 or 20 hour work week, but 4 hours a week seems extreme. Plus, if you are doing something you enjoy, "work week" doesnt have the same meaning as a traditional 9-5 job.
Assuming you are talking about the Tim Ferris 4 hour workweek (http://www.fourhourworkweek.com/) then yes, but that's not really the problem. The problem is the unreliability of the pay when you work for yourself.
I think that I'd just work on other (potentially/hopefully) revenue generating things in the remaining 36-96 working hours, so it's hard to see how it applies...
