I really don't know why I get involved in these silly arguments.
Who says it took Walter many months to remember all his songs? He had been writing them down in exercise books from 1948 and had been singing them and playing them on the melodeon, to himself, right up to the time he was 'discovered, so he had no need to 'remember them'; they were already there.
Who says the pub is in any way a desirable place to sing traditional songs. Sam Larner sang at the Fishermans Return in Winterton - he sang the same song every week for most of his life. Where did he sing his other songs? He told the collector "the serious singing was done at home or at sea".
Pub singing in Ireland is a comparative latecomer, as is the playing of music. Within living memory virtually all singing and music took place in peoples homes at country house dances. Musicians have told us that the music started to go downhill when it went into the pubs. Being able to sing in a pub does not make anyone a good singer or more 'versatile', just an extrovert.   
Your preference for Harry Cox is, as you say, subjective, and without qualification it is about as important as your telling us you prefer white socks to blue ones.
Walter Pardon was a thoughtful and generous man. He often said he regretted never having met Sam Larner and Harry Cox, both of whom lived within 20 miles of him. He would have been mortified to hear a couple of folkies like us arguing the toss over which of them we preferred, he probably would have banged our heads together (no he wouldn't, but I wouldn't blame him if he had). You seem obsessed with competition: better, worse, more important, less important - I think your CCS (Comahltas competition syndrome) is beginning to show through.
Without the Walters and Sams and Harrys and Phil Tanners and George Dunns and Robert Cinnamonds and Mary Ann Carolans and all the other generous people who gave us our songs we wouldn't be having this conversation, I wouldn't have had nearly half a century of pleasure and we'd have no songs to sing - and neither of us would have heard of Peter Bellamy.
Jim Carroll