If Larry and Adam were disposable they would have been dumped before the original record deal was signed as they had plenty of offers that would have involved dumping one or more of the members and they turned them all down.
I believe there was a talk of sacking Larry at some point. I don't remember whose suggestion it was - some record executive or someone like that. and yet, the band stayed together...
I love, respect and admire Larry but I know that he's not the best drummer in the world (as he has said himself on numerous occasions). I'm sure Egde, Adam and Bono could find a better drummer if they wished to. I'm sure Larry, Edge and Bono could find a better bass player. they didn't. so it looks to me Adam and Larry are not disposable. at least not to their band-mates.