I'm seeing three kinds of professional services firms:

1. SAAS (which trades at a high multiple)

2. Agency (in which the "business" is putting different specialists together under one roof, e.g. digital marketing), and

3. "Specialist Proprietors" (where the business engine is often the person you would think would occupy the CEO role -- Dentists Clinics, Accounting Firms, Chiropractors, etc.).

These "Specialist Proprietors" of the third group look attractive because they have recurring revenue , known brand, and a defendable geographic area. But much of the value of the company is tied to a principal who has all the sales contacts and certifications required to keep the business in operation, who could leave at any moment, and whom you could not readily replace without an advanced degree or certifications. People seem to go to their dentist because they like the personal relationship with him or her, but I wonder if there is a Supercuts model here too where some people just don't care who it is that cuts their hair if the location is convenient.

Has anyone seen a successful search acquisition of such a firm (not a roll-up) by a non-Specialist Proprietor?