Yes they did. And this is why a reunion would probably only disappoint fans.
Unless Zep could find a drummer with the skill and the sound of Bonham (Dave Grohl is, IMHO, the only one who might fit the bill) there is no way they could capture the "bombast" of their sound.
I read a recent interview where Page laments playing together at Live Aid in 1985. They used Phil Collins on drums and Page said that Collins basically sucked and treated the whole thing as a joke.
Page was right.
As big as a Zep fan as I am, I think history shows that it would probably be best if the three of them never perform as Zeppelin again. I doubt they could rekindle the magic of what they were.