I'm not arguing that he was lucky as the bass player. I'm arguing he was lucky to be the 4th member of group that comprised Page, Plant and Bonham. With Grant's astute management these could have released anything and been superstars, conversely those same albums (with the exception maybe of 2 and 4) could have been released by any other group of musicians and I doubt they would have resulted in that group becoming the global superstars that Zeppelin were.
I'm not dismissing Jones and bass players who are often at the very core of a group's success (Lemmy, Jack Bruce, Geddy Lee, Chris Squire, Les Claypool, Roger Waters, Paul McCartney etc., etc)
To use a sporting analogy, I don't care who was on the Bulls roster in the early 90s. They all ended up with championship rings, but were lucky to be in a team that included Michael Jordan. That doesn't make them any better or worse as basket ballers, it's just s statement of fact. Remove Jordan from that team and I wonder how successful they would have been. Likewise for guys in the current Barcelona squad ,who are lucky to be in a team that includes Messi, Suarez and Neymar. Transfer that same player to another club and they are very unlikely to experience the success they would experience at Barcelona. Those three though are superstars where ever they play.
I probably still haven't made my point very well, but perhaps there's some who see what I'm trying to argue as basically blasphemy and could never be convinced or even acknowledge that even if Jones wasn't lucky, he was at the very least, fortunate.