... that Sam's creators just didn't find him particularly interesting, which explains why they didn't bother to give him proper character development and his story a proper ending:
'I always said to him [John Simm] that he'd got the Tom Cruise rose in Rain Man: his job was to make what Phil does make sense....Without Sam, Gene doesn't make sense; without Gene, Sam just wouldn't be interesting enough. They compliment [sic] one another perfectly'.
- Matthew Graham
Taken from:
http://community.livejournal.com/lifein1973/859493.html As I've suspected for a while, Sam was just a foil for Gene.
(Well, okay, maybe I shouldn't write 'creators'. For all I know it's just Matthew Graham. Who so far has the distinction of having produced all the annoying soundbytes about the show. Haven't heard anything annoying from the other writers yet, really.)
I'm beginning to develop a distinct dislike of Matthew Graham. I should probably stop reading interviews and articles by/about him.