I've had a LONG run of possible buyers who exhibited every buying signal, knew my rates then dropped out just before the deal closed. Is it something in the air? It's never been like this before.
People can be flaky with short attention spans. The followup process can be painful because you don't want to be a hardsell but a lot of times that deal won't close without you following up. Wait a week, check back if they're interested. Reach out again two weeks later. If they don't respond, move on to other prospects.
It could be totally independent of your fees since the problem you described doesn't mention them balking at what you charge or asking you for rate cuts or auditions. But your site should have a clear message and quality content with high engagement that shows you can be trusted-- case in point, I had a tougher time getting marketing and consulting work in games before I had a built up presence on Gamasutra then branched out to other sites in addition to my own blog.
It's sounding like an unsure buyer vs. fee-cheapskate issue here.