Unfortunately, paying someone well does not necessarily mean you're going to end up quality either.
Good people, who are starting out, often undercut their rates to ensure they stay competitive with the plethora of options available to the buyer in the market.
Suppose, I value my work at $30 an hour and I don't have too many projects to show for it but someone else is offering the same skills at $15 an hour but they have a whole portfolio of (somewhat-)shoddily done jobs, 99 times out of hundred, I will lose my contract to the $15-an-hour competitor.
My only option: Quote $15 or less an hour and build up my portfolio. Unfortunately, once you 'sell' yourself for $15 an hour, no one will want to pay you more than that for subsequent projects. Sadly, what no one understands is that $15 an hour only buys you my time; it doesn't buy you my motivation to apply myself to the job. :(
In my experience, this isn't true. I only freelance part-time now, but I've managed to raise my rate by $10/hr for each separate client I've landed in the past 3 years. Granted, I haven't raised my rates on any of my long-term clients in that time. But the evidence I have (and what I've read) suggests that above a certain price point, many clients have a much higher ceiling for per-hour rates than you'd expect, and that the clients who are strongly price-sensitive are often the ones that you'd as soon not take on.