I'm sure money plays a big part. Many can walk into a six figure job. Not bad for someone in their late 20's.I don't really know why so many Nukes bail after their first tour and it may be as you say, but I don't feel that the Admiral's interview has a correlative affect on retention.
Nuke training can pay big dividends. We know a couple of retired nuclear trained aviators (06's) who started out in the civilian sector at over $350,000/yr.