Well, usually I'd say that this is mostly coincident. What I mean is that Apple usually updates their machines depending on their own schedule, not depending on launches of new technologies. That means that Apple, as one of the very few, is not putting a new machine on the market every time that new technologies surfaces. As such, Apple is often seen as being "slow" and "kinda last year". Although unfair, I think that Apple's reluctance to embrace high-end technology has contributed to this reputation.
In this case however, Apple is going to release an updated MBP within the next few months, and Sandy Bridge just happens to be "recently launched". Also, Sandy Bridge is not "high-end technology" although it is cutting-edge. As such (and as usual), you should expect SB, but not the high-end versions. That's all.
I would say that there is a high probability that SB will make it into the next MBP, but also the next MB and MB Air.