Remind me how you can safely rip off a soldered on heatsink from a flimsy piece of silicon.
Also, I read that using TIM is in order to reduce costs, not because the TIM process is much cheaper, but because the soldering process is easily botched and leads to more failures. The TIM process gives good enough performance at a better success rate. Also, I heard that the small gap between the heatspreader and die is good for big heavy heatsinks, as they tend to crush the die otherwise.
All of this I got from a Toms commenter who probably posted above me already