Pakistan made less run in their innings and also they do not have the bowling line up to defend this small target.
Overall it was a bad series for Pakistan. They have lost both the ODI and T20 series and it will shatter their confidence before going into T20 World cup. They should have shown better performances specially in T20 matches.
Out of the 6 matches, they lost 5. So overall, it was a bad series. But there were some brilliant individual performance from the Pakistan players. Fakhar Zaman and Babar Azam did well with the bat, while Shaheen Afridi was impressive with the ball. So it was not all doom and gloom. There are a lot of positives that they can take from this tour. And for the T20 world cup, they definitely have an advantage, because the matches are going to take place in UAE and Oman, and the players are well suited to those conditions.
The individual performances does not matter much when they can't contribute in the winning of the team. All such efforts go in vain and no one remember them if the team does not win.
I must appreciate the England team who despite the B team, played superbly and got an historic win.