lots of people who go to top residency programs end up staying in academics (often at the same programs which pay junior faculty as low as 130k). Of course many go into private practice and other things and do quite well for themselves, but there isn't much correlation between where you train and your income as some of the very worst psychiatrists make the most. Its probably a bimodal thing
As for forensics, given the current top fellowships are in places no one wants to live, and fellowship in general aren't terribly competitive, even the top fellowships accept people who shouldnt even be allowed to practice medicine. the competitiveness varies year on year and for some programs might depend on how many internal applicants they get. That said, I know this year one applicant who was from a good residency program who offered to do a top forensic fellowship for free and was still rejected. I know an internal applicant who was also rejected from the home fellowship. This speaks more to personality pathology (in both residents and faculty) than it does to where one trains.
Needless to say, all things being equal, one should train at the place that will give you the best training for your needs