Led Zeppelin were, as I recall, at that time - THE top band in the world. That is they defined what a 'rock band' was. If in OTL music developed slightly differenetly, that is because Led Zep were not there to lead the way!
The only question for me - is can they maintain their high standard, can they keep up with the continual touring?
The Rolling Stones over the years have kept going, some of its members have changed, but it has still kept going.
Seems the main influence is the 'singer'. Perhaps with Led Zep., it was an excuse rather than a reason!