The Bruins despite losing their top 2 centers are still in cap trouble. They currently only have about 400,000 in cap space. To acquire a top play they would need to clear significant space. Up until this point they had been unwilling to do so.
If the Bruins feel the need for a center they would have to pay a hefty price. However, the core that broke regular season records last season deserves another shot at a Stanley Cup. If acquiring Scheifele is what it takes to bring the Bruins back into contention it could be well worth the price.