You are right the innings of Pakistan was far better than the second innings. They lost because of poor batting otherwise they could have either draw the match if they had good lead. Pakistan bowling has not been as it was earlier. I am not sure taking action against the bowler will be the right thing to do who opted out of the test series.
This is not something new, Pakistan team is always having a whitewash at Australia. They are not able to manage pressure when playing at Australia. See they have good advantage in first innings but were not able to capitalise that advantage in second innings. Babar Azam who is backbone of Pakistan batting was not able to score even a fifty in his six innings, his highest score was 41. Players like Babar Azam need some break they are over hyped.