What makes you think Parker isn't a good captain? The only time he's got to be captain is when we're origin depleted and had no chance anyway, I don't think his W-L record as captain is a fair indicator.
Either way I don't think Thaiday has what it takes, he's inconsistent and plays 1 good game out of 10, Parker plays 1 bad game out of 10, that's the difference.
I'm not being over the top but I can't remember the last time Thaiday had an awesome game where he had me thinking "Thank the NRL gods that he's not playing for anyone else" and he's probably our highest paid player.