"Most of us know teachers who teach very successfully in a textbook-lecture, teacher centered style and have had terrific student achievement doing so." (Nunley, 2006, p. 103)
It's possible, right?  It is entirely possible that your classroom is full of auditory learners who don't mind listening to a bald guy talk while swapping slides.  It is entirely possible that all of your students are satisfied taking notes and look forward to college lecture halls in their not-so-distant future.  If memorizing and regurgitating facts are what you're looking for AND if students are satisfied AND if parents endorse this type of teaching AND if administration is kosher with the results, then keep doing what you're doing.  

If the above commentary describes your situation, keep doing what you're doing. 

Chances are pretty good that your classroom is different.  It's broken.  It needs fixed.  For your students' sake...you (and I) do NEED to differentiate. 

Any questions?