Just because you're billing $40/hr doesn't mean you're well above marginally employed.
We're talking about a 2 hour gig here. There's likely to be at least 2 unbillable hours involved in a 2 hour gig gig, so your rate is already cut in half to $20/hr.
Once you start taking into account all of the unbillable hours (including time spent finding gigs) and all of the downtime between gigs, a $40/hr rate could very well mean you are below the poverty line.
We're talking about a 2 hour gig here. There's likely to be at least 2 unbillable hours involved in a 2 hour gig gig, so your rate is already cut in half to $20/hr.
Once you start taking into account all of the unbillable hours (including time spent finding gigs) and all of the downtime between gigs, a $40/hr rate could very well mean you are below the poverty line.