I just said in conversation:
Au fil des années, j'en suis venu à me dire que ce que je faisais là ne serait jamais reconnu à sa juste valeur. Ce n’est pourtant pas faute de nous décarcasser pour faire en sorte que ...
{ pourtant / quand même / tout de même / pour autant }
In the flow of conversation, I can usually choose intuitively which of the four contrasting phrases above to use, depending on a surrounding expression, but as to the "ce n’est pourtant pas faute de ...", the why of the near-exclusive use of "pourtant" eludes me. I wonder why I almost never hear other contrasting phrases than "pourtant" used in this particular expression?
As far as I know, "pourtant" seems to imply a rather stronger contrast between the two ideas being presented. And whenever you say "ce n’est pourtant pas faute de ...", a strong contrast is indeed intended. I wonder if this goes some way to explaining the why?