I genuinely think the reason is something more than just cricketing skills. This Australian team had some good young players, but was still weak and very vulnerable after the home defeat to South Africa. Australia were at their most vulnerable point and if there ever was a chance of an asian side winning in Australia, it was a few weeks back. I knew winning in Australia was tough, but after seeing Pak's performance in England, I honestly believed that Pakistan had a very good chance of drawing the series in Australia and who knows, if they could've nicked the day night test amd drawn the other two, they could've even had a historic series victory in Australia. Pakistan are vulnerable against lateral movement but generally play well on pitches with true bounce and I thought they might do very well in Australia and their batsmen would relish the conditions there.
But what I saw was something more than a lack of cricketing skills. Pakistan are poor in batting out a final day and I've seen that in other places but they definitely should have drawn both the MCG and SCG tests, especially with all the rain interruptions. I don't think they are as poor as they batted in the last 2 days in Australia at Melbourne and Sydney. Their batsmen are all temperamentally good and can play attritional cricket for hours at a very slow rate. But they way they started playing reckless shots while trying to save a game like Hafeez did at Edgbaston on the 5th day was mind boggling to say the least. Experienced batsmen like Younis and Misbah were playing reckless shots while Yasir showed more resistance than the more celebrated batsmen. Only Azhar Ali came out of the tour with his reputation enhanced and fair play to him, he fought tooth and nail to save the tests and didn't choke under pressure. And I'm sure these batsmen wouldn't have played those shots if it wasn't the last day of the test. All that tells me that Australia have got a psychological stranglehold over Pakistan and the latter are in a mental rut against Australia in Australia. This needs a mental conditioning coach than anything else.
Mental conditioning can help somewhat, but it won't help much. Leave AUS, PAK has lost several matches against SAF becaue of the batting of Pollock, Boucher, Symcox, Boje ..... even Robin Peterson, after getting better of Kallis, Smith, Kristen, AB, Amla or Cullinan. Tough, bad a$$ players who'll not throw the towel & made sure that PAK is in the game - bowling tight & taking catches, instead of waiting for the tail to gift wicket. Similarly, while chasing, several times I have seen PAK folding to SAF for last 5/6 wickets going down for 60/50 .... even 20 - that's because SAF will never allow a gift boundary, never will drop a sitter, never will miss a run out with a wrong call & they'll never allow you to relax, even when 10 is required in 5 overs with 5 wickets at hand.
These are matches that you don't lose for skills, neither for experience - these are matches where you have to count every ball & think every moment. And, this against every thinking Captain of any team - take your pick - Tubby, Arjuna, MSD, Ganguly, Clarke, Fleming, Mac........
In fact, PAK's performance is probably best against Steve's AUS; should have won the Hobart Test, won a WC match, won an ODI series in AUS & almost won a Test at Colombo - that's because, since 1900 (that's from Monty Noble, Clem Hill, Victor Trupmer, Armstrong, Herbi Taylor, Bardsley, Bradman, Hasset, Johnston, Benaud, Simpson, Lawry, Ian, Greg, Hughes, AB, Tubby, Steve, Ponting, Clarke, Smith - compared to this list, when I think Misbah taking PAK to AUS or next time Azhar will take .....

), Steve Waugh was the most ordinary AUS Captain, when it comes to tactics.