From my experience at our local parish over the last two decades, many clergy have already written off the Vatican bureaucracy.  One example is when I asked the head vicar when the precepts of AL would be implemented and he said he had been mercifully pastoring "in this fashion" for many years.  Another example (during the reign of JPII), a different priest was fond of reminding the congregation that folks in the Vatican had "no clue" as to how things work in real life.  In that sense decentralization has already occurred, albeit in an informal, non-canonical way.  As with most facets of RCC teaching, many have learned to accept the ongoing disparity between church doctrine and pastoral practice so a formal "decentralization" would actually lend a little much-needed credibility to the beleaguered church.