Marketing as science has emerged as a theme and all debaters claim rigor and quantitative studies, yet they have contrasts. How do we reconcile? Doesn't feel like true science, but rather validation of opinion.

Very true. To put it bluntly, Fader's and Hanssens' work are peer reviewed in the top marketing journals, meaning that they have (both repeatedly) validated these ideas with data and against panels of peers (sometimes people like me) who challenge them on every aspect of their work before accepting it. On top of that, the field continues to try to dismantle and disprove those ideas - and we get rewarded if we were to accomplish this. Yet, their work still holds. Interestingly, some of the non-peer reviewed work presented: Rubinson's, Wood's, and Schreider's are consistent with those theories. They present more contextualized, execution, and how to deliver on these concepts. Conversely, 'mental availability' from Dr. Sharp is not generally know in academia, and is not itself a peer reviewed work, living instead in his two books.