I don't think Tom saw himself as a "captive," but rather a wannabe brother to Michael and Sonny. Tom always chafed at Michael keeping him out of the loop, and there's a foreshadowing of the distance between them in the flashback scene at the end of II when Michael announces he's joined the Marines. Tom tells Michael that he and Vito went to a lot of trouble to keep him from being drafted, and how he and Vito had discussed Michael's future. Michael is furious and sneers," You discuss MY future with MY father?"
DT, you've pretty well summarized their relationship. I've always maintained on this Board that Michael developed an antipathy toward Tom that was born, in part, from what you cite in the flashback scene. Add to that Tom's failure to protect the family. One could even throw in the seeming favor that Vito showed toward Tom as perceived by Michael. Although Micahel chose to estrange himself from his father, he may have rationalized some of that estrangement by blaming Tom. It starts early in the film: why would Michael introduce "Tom Hagen" to Kay?
