The choking tag has been historically associated with South Africa but looking honestly at Pakistan's World Cup record before and after 1992, Pakistan have imploded on many occasions on the big stage.
1975: Pakistan had a number of County pros with experience of the one-day competitions in England so were one of the stronger overseas teams. In a virtual KO vs West Indies, they set 267 to chase and reduced WI to 203-9. Yet Deryck Murray and Andy Roberts took them home.
1979: Admittedly a tough runchase of 294 in the SF against the world champions, but Zaheer and Majid bat like a dream to take Pakistan to 176-1, yet we collapse to 250.
1987: Pakistan were arguably the favourites going into the tournament. Playing at home, Pakistan win five from six group matches but choke in the SF vs an unfancied Australia.
1996: Possessing arguably the most complete team they ever took to a WC with most of the playing squad in their primes, winning four from five group matches, again in home conditions, and this time defending champions - Pakistan contrive to lose to a weak India side in the QF. This's the one that got away.
1999: A slightly overrated side with many players past their primes, but a stellar bowling attack. Reach the final, and I think my post typing this out is longer than the Pakistan innings.
2007: Despite drawing the easiest group of all major nations, Pakistan contrive to lose to both West Indies and Ireland despite possessing big names although admittedly likes of Inzamam and Yousuf were nearing the end.
2011: Contrary to what most think, Pakistan didn't have a great ODI side with too many one dimensional batsmen like Shehzad, Younis, Misbah and Shafiq. Reaching the SF was probably right for that team, but losing the Mohali SF having dropped so many catches and chasing so poorly counts as another missed opportunity.
Pakistan were far from the best ODI side in 1983, 2003, 2015 and 2019 and did not deserve to win so cannot count that as choking. Reasons for that are varied - 1983 side missed Imran's bowling, 2003 team was well past their peak, 2015 team was appalling and 2019 was middling.
But to answer why we've not won the most recent World Cups - it's simple. The ODI game has evolved greatly from the 1990s formula of score 250 and back your bowlers to defend it. Now 300 is par and Pakistan don't have the batting firepower. Too many young batters lack game awareness or ability to assess conditions. Meanwhile reverse swing has been diminished because of two new balls rule. And our fielding remains well behind the top sides.