I've come to realize something about Galahad: actually, he didn't have Lord Camelot in life, he must have acquired it after death as a Servant. In OCIV Mordred reacts with surprise at seeing the shield, and exclaims that "That's my Round Table! Was this that bastard Galahad's idea?!", implying that during life Galahad did not yet wield the core of the Round Table as his shield. If Mordred didn't know that Galahad had a Round Table shield, it can be assumed he didn't use it in life. The actual shield he used in life was probably the pale red cross shield that we see in Mashu's bond CE and is mentioned in Requiem, which is the mythologically accurate shield.

So why does Galahad's shield become the Round Table? It's probably because of the "Inheritance of the Seat of Calamity" mentioned way back in Fate/Unpublished materials. That was mentioned as the thing that allowed Galahad to manifest the Round Table as his shield, because he was given the right of the Seat of Calamity due to his seat being the Siege Perilous of the Round Table. This is probably something that happened after he became a spirit, right? Or, at least, it must be something that happened after Camelot. If you think about it, Galahad's probably one the few mythological powerful Servants who got even stronger after "death", rather than weaker. His greatest feat is gaining the Holy Grail and ascension, right as he "died". Lord Camelot, it's now fair to say, was probably also acquired after his life was over.