I just read a few of the beginning posts, but here are my views as a graduating CA-3 in June. I am doing a pain management fellowship next year, and have no interest in hearts, although I have done more than enough (4 months in tristate referral center that is the flagship hospital of my program), so I can give you a somewhat objective and experienced opinion.
1. cardiac anesthesiologists will never "starve" b/c if you can do a heart, then you can also do anything else in anesthesia. That is, they can easily do the general cases. The heart is the most important organ followed by the brain for anesthesiologists. so, cardiac anesthesiologists will always be in high demand in the OR world, simply b/c they can take are of sickest patients (i.e. patients w/ terrible heart disease).
2. its true that the number of routine cabg's are declining and that Cardiac surgeons are probably going to have trouble in the future, but see #1 to understand why cardiac anesthesiologists will not be affected. more and more cases are now valves.
3. many if not most private groups do not require a fellowship to do hearts. most of my CA-3 graduates are going into private practice and doing hearts some of the time. many routine cabg's where the patient is not all that sick do not require TEE. when they do, a cardiologist can come in and do it. many community hospitals simply have in a central line and at most a swan for the harder heart cases. TEE would be provided by the cardiology dept or a general anesthesiologist who "learned on the job". if I was going into private practice, I would be VERY CONFIDENT to do most hearts in the community hospitals after my four months of cardiac rotation. my hospital had some of the sickest hearts and most of them were valve cases. i know how to do a basic TEE exam and would learn more by trial and error as a practicing anesthesiologist.
4. many, many general anesthesiologists do not like doing hearts simply b/c its more stressful. they are some of the more challenging cases. thus, that's why the young attendings, freshly out of residency, end up doing them.
Hope this helps.