"What is different about today is the degree to which some bishops are more or less willing to openly challenge the pope..."
Untrue.
Archbishops Hunthausen, Weakland, Bernardine, Mahony, Hume, Martini, et al., challenged JPII.
Archbishops Kasper, Murphy-O'Connor, Nichols, Wuerl, et al., challenged Benedict.
It happens to every pope including Francis.
So, what else is new?