If MS had really wanted to go for the throat as you imply, then:
1) they would have bought Epic in 2005, not 2008.
2) they would have bought Immersion rather than settle with them.
IMO all you have shown is evidence of sound business practice in the face of competition. You seem to be painting Sony as the underdog that needs our pity, but remember its position of sheer dominance very recently. MS had to execute a plan to mitigate that dominance. How else do you think they should have approached the next generation, other than aggression? IMO MS have been far less aggressive than they might have been.