The Mac Mini is an entry level product appealing to a small market... I reckon Apple switched to 28W CPUs to promote the Energy Efficient thing they have going around with their lower tier Macs and to push power users to the (more expensive) iMac.
I don't believe there's any decisive evidence that Apple wants to drop the Mac lineup. They definitely seem to be moving their minor products like the Mac Pro/Mac Mini to longer release cycles, though, probably in response to sales volume.
People buying 15" MBPs need a good CPU to run productivity software like Adobe or FCPX, and no matter how many ****-ups they've done in the past, there is no way that Apple is stupid enough to ignore it's target market. They wouldn't have lasted this long otherwise.