Are you at all, in any way willing to entertain a viewpoint that suggests that those gentlemen have their titles dropped possibly because they have become synonymous with their crafts and a lifetime of achievement that-at least in the case of Dr. Sagan has spanned generations (Dr. deGrasse-Tyson's work and personality on the cusp of enjoying the exact same), and their names closely associated with a deep personal connection to the dissemination of science as a form of consumable entertainment (that also happens to inform) and that this maybe serves as an important distinction between someone who is appreciating their first bit of notoriety for their scientific accomplishments?
I personally think they should all be addressed by the titles they've worked lifetimes to earn, that anyone who holds a formal title such as Doctor should be addressed as such in a non-casual/non-informal environment, but I'm also willing to entertain that this is a possibility for why the difference may exist between Dr.'s Sagan, deGrasse-Tyson, and Bouman. And yes, there are probably, most likely others that are far less nuanced and charitable.
Would you be willing to entertain that viewpoint?