Maybe one of the reasons for not responding- among man - is the unwillingness, the risk, the inevitables, of an honest and full response. The "dubia" is a call to extremes, an either/or, and Pope Francis is either not prepared for the consequences or the process. 
He knows with a fullness that the rigidity of doctrinal purism is so totally wrong that it is the equivalent of "evil". Winters, I think, is right (i.e., correct). If the church is not a museum it is a real, organic life stream of community, an amoeba of sorts that has evolved from a single "Cell" (sorta) but is still infantile, nowhere near potential. The call is to a burst of change with precedence only in the Eucharist itself.  It is a call for the church to jolt from its shell to the pursuit of Jesus rather than hide under the mythic rock of institution. Jesus said that he would build "upon" the rock, not under it. 
The dinosaurs have had their day, they became grotesque, unsustainable, beautiful - in a way. It is time.