Because the two were such icons in not just rock but music itself. People just like to challenge great things, like coke and pepsi

but i personally dig on floyd more their wasd more of a message in their music.....Zeps in like a close 2nd i love how poetic some of their shit was and how hypnotic Jimmy PAge was

__________________
"But who can unlearn all the facts that I've learned
As I sat in their chairs and my synapses burned
And the torture of chalk dust collects on my tongue
Thoughts follow my vision and dance in the sun
All my vasoconstrictors they come slowly undone
Can't this wait till im Old?
Can't I live while I'm young?"
"Chalkdust Torture"-Phish