Lot of reasons for that.... leading the reasons is that it's HARD.
I have seen very few drummers in my life that could, or would, style themselves after Bonham.
Oddly enough... I am similar to Bonham in one very significant way. No... not talent and ability.
No.... what I mean is nearly every drummer in rock/pop follows the bass riff. Bonham, and me, more often follow the lead guitar. I suppose is the jazz influence. It's natural for me and I think that's because I began music playing the trumpet, (thru my college days), and am just naturally more geared toward the melody. - JamesJM