To me, one of the most interesting things about the band is the strange role reversal that is part of their sound. The guitarist is who is setting and maintaining the tempo with his delay(s), the drummer and the bass player are adding groove but they can’t change the tempo or the whole thing is going to sound like shite. It’s almost like the lead guitarist is a drum machine in disguise. 
I’ve never heard them live, and I’ve only heard ‘Achtung, Baby’ once or twice, but I don’t remember thinking ‘Oh, they’ve just done a ton of overdubs in post production.’ I’m quite amazed that the band is able to replicate their studio sound live, considering how much of their sound is based around The Edge and Daniel Lanois messing around for the entire morning before the rest of the band comes in to get exactly the right setting for the rig.
I can’t blame The Edge for being so conservative - the way things are set up, if he drops a clam, he’s got to hear it another 100 times before it’s gone away. Bono’s the one who’s got the freedom to go in and around the cracks and that seems to be the way they all like it.