People who don't refer are not Ideal Clients. If you choose to keep them as profitable non-Ideal Clients, that's your prerogative. The truth is that your clients don't really know whether or not their friends are "all sorted out." It's hard to read a person's mind and know exactly what they are thinking and feeling. My belief is that when a person is unwilling to refer and introduce you to others it's because they either don't trust you completely, or aren't all that impressed with the work you've done for them. That can either be because of them, or you, or some combination. My advice is to continue to make progress with the value you deliver for your clients, your communication skills, to have the referral conversation at every Progress Meeting, and do whatever else you have to do in order to meet people who might become Ideal Clients.