Let alone T20I against England, I would not be surprised if this same team beats literally any team on its day in next 2-3 years.
People feeling disappointed by this series loss are either too young or naïve about Pakistani cricket culture. It has always been like this. They loose and win under the most unfavorable conditions. The same Pakistan that lost like a minnow against WI in WC2019 went on to thrash three SENA nations including both the finalists. They fought hard against Australia as well. Then they almost lost against Afghanistan. I once heard Rambo saying that if Pakistan wins the 10 test series against top sides, they can still draw or loose against a non test playing nation.
Why is that ? the brand of cricket we play is non methodological and our selections are emotionally structured based on raw talent we see in players. We never adapted the data based game plan model that other teams adapted 15-20 years ago and instead we even today rely upon two or three players firing up. Yesterday it was Babar Azam and Rizwan and nobody fired in bowling so we lost. Same set of players in next series will produce performances and Pakistan will win again and this will continue.
This has been the story of Pakistan cricket and it will always stay the same until we as a nation think differently which we never will. Pakistani cricket team has never been a world beater like most people think. It has always been an extremely dangerous team that sits on 3rd to 5th in rankings but unlike others in same group of it can pack an extreme level punch that can dismantle the top teams when it feels like it, while lose to bottom teams or get white washed when it feels like it.
What you said may be right, but then again, it's still not good.
It gives fans unrealistic hope that perhaps Pakistan can show some consistency, perhaps Pakistan can win a series against a top 4 team, but that's the issue.
That word "perhaps" doesn't do any good to the team's fan following, because people know that you will probably lose to cheap teams and might beat the big teams, but that's not what anyone wants.
If any Pakistani is content with losing to teams feeding at the bottom of ICC rankings, but somehow beating the best in one or two games, you are lying to yourself.
In reality, we want a Pakistan side which truly dominates the world across all formats, and does not repeat the same mistakes.
We have been the same team throughout our history, and that is not an achievement, it is a disgrace. It is disgraceful how we have never been able to implement any sort of consistency post Imran Khan's captaincy. India went from being an average team to a world-class team. New Zealand went from being minnows to world-beaters. When, if even, will that happen to Pakistan Cricket?
The reason you see so many doomsday posts is because nobody wants to see a comeback after every single game, people want to see the team win and force the other team into tough situations.
There is nothing more satisfying for a cricket fan than watching their team absolutely pulverize another team, but when you're on the receiving end of the spectrum, it's a horrible feeling.
Even if being "mercurial" is part of Pakistani culture, it is wrong. You shouldn't praise being the most inconsistent team, because whilst some may see it as a compliment, it isn't. It just means that the management, the players, and the fans are all delusional in thinking that the team will be anything more than what it is.
Of course, I think that there are a lot of things we can change with the right mindset which will help improve our cricket greatly.
We don't have players even half as talented as the Big 3, but we sure as hell can be among the top 4 sides in the world if we put our backs to work.
Every big team starts off in the mid-table and works its way up, and maintains that position for a few years by providing consistent performances. Who knows, in a few years, one of the Big 3 (likely Australia in my opinion) might suffer due to various reasons, and there could be a place for Pakistan to take if we work hard enough.
But the first change comes from the mind, letting go of this "mercurial cornered tigers" mentality and instilling a winning mentality, one with the ability to identify areas to improve, learn, and most importantly, adapt to difficult situations. A few bad performances are excusable, losing to a C team is not.
Anyone who takes pride in Pakistan being mercurial, and thinks that the 1992 Cornered Tigers was a step forward for Pakistan Cricket doesn't need to look too far to see how poorly it has affected our cricket.
Right now, we are luckily a mid-table team, and we have it much easier than Bangladesh, Sri Lanka, and West Indies, but that means nothing if we are unable to use our position to at least try and punch above our weight and put up a fight once in a while.
A lot of people say that our fans have unrealistic expectations, but I think the issue is the players. Our players take satisfaction in doing the bare minimum. Our fans also take satisfaction in beating a crippled Zimbabwe team. It's an issue of mentality, it should be very hard to satisfy fans with a win over a team like Zimbabwe, but that isn't the case. Until this mentality changes, Pakistan is, and always will be a mediocre team who fans hype up with regards to this mercurial and unpredictability tag which has swallowed our cricket and left it to rot.
