Sir, without a replacement aircraft the youngest buff is projected to retire as an 80+ year old airframe. We could put new tires and engines on them, but at some point metal fatigue will have them disintegrating in flight. Fortunately the ejection systems are much newer and more reliable.
With the renewed Pacific focus the mission need for bombers doesn't shrink, so quietly bedding them down in the boneyard without replacements isn't a good option.
Even if fast tracked, seed money to encourage development of prototypes shouldn't significantly compete with KC-46 delivery. KC-46s should be showing up at Air Force bases near you before a new bomber design is even chosen for full development.
This does bring the issue of acquisition and budgeting reform to the surface again. At some point the services may need to relinquish control to DOD for prioritizing spending rather than getting an equal share and prioritizing internally within the services.