So again, you believe that that was the plan before they even hired you, or was it just that that was how it worked out?
If you thought it was their plan right from the start, was there a reason you took the position in the first place? Not trying to be nosy, but I'm getting into a bit more consulting and it's helpful to be able to draw on other people's experience.
On some level it's also good to know that it isn't just something that happens in optometry.
That is a common story.
Hire a new guy. Everyone in the practice takes less call, and less holiday call. The net cost is generally manageable: startup salary, malpractice, maybe a new tech (but usually not, just a shifting of responsibilities), perhaps a small capital equipment investment (but again, often not), and hospital application and society membership fees. Usually the new associate has met his net added cost--i.e. "covered" himself before the end of the first year, sometimes well before then. Once done, all that is necessary is to get him to do some more work, and the earnings go straight to the partners. Keep him interested with a little taste of a production bonus, maybe even promises of a buy-in plan, perhaps promise a share of a surgery center, and pretty soon, he has developed a full, busy and profitable practice.
Then you screw him. Do things to him and his practice that would make anyone unhappy. Renege on the partnership deal. Cancel his contract.
Now you go and hire a new associate. Only this time, you don't have to wait for him to build up a practice; his predecessor did that for him. He becomes profitable right away. And guess what, he is motivated by promises of a bonus and partnership just like the first "associate" was. Good deal.
Serial hiring can be very profitable. And you know, those expressions of pained regret when someone interviewing asks about the guy who left: "Oh, he just never seemed happy." "We tried to help him, but it just didn't work out." "He wanted to live somewhere else in the country." (Good thing if he had a non-compete locking him out.)
There are plenty of these kinds of guys around the country. Their practices are always advertising for new people on the AAO Professional Choices webpage, and in the throwaway journals. Yes, local docs are often reluctant to say what they think of other doctors, even ones that really have bad reputations. They want to avoid trouble.
Here is a hint: if they don't say great things about that doctor, if there is even the slightest hesitation, take that as a bad sign.
And call the former associate doctors. Try to track them down and get them to talk with you. That is probably the most helpful thing to do. Be persistent but polite. Keep what you hear in confidence; you are trying to make a personal decision, for yourself, not others. If there is reluctance to endorse the practice, that is a sign the practice was not a good opportunity. If they say they have agreed not to discuss the practice as a condition of some settlement, you can draw the obvious conclusions.
Call some of the local optometrists, too. They are usually more ready and able to say what they think.
There are a lot of predatory older docs that do crappy things to new hires and have all sorts of sociopathic rationalizations for why things don't work out. It is really a shame more of them aren't outed for what they are and what they do.