Because they are not good tacklers like AWB. Ricardo Pereira makes as many tackles as AWB btw.
They all attempt many tackles but only AWB wins at such high rate.
| Total Attempted Tackles |
Ricardo Pereira | 6.1 |
Sidibe | 5.8 |
Jonny | 4.5 |
AWB | 4.5 |
Ryan Fredricks | 4.2 |
Aurier | 4 |
Azpi | 3.4 |
Digne | 3.2 |
Reece James | 3.2 |
TAA | 2.8 |
Chilwell | 2.8 |
Shaw | 2.6 |
Robertson | 2.5 |
Zabaleta who was one of the best FBs in last 10 years in PL averaged 5.9, 5, 5.1, 5, 4.7, 5.1 tackles attempted for ManCity.
This simplistic "More tackles = bad positioning" myth should die and fast. That might be applicable for CBs but never for FBs who deal with wingers 1v1 all the time.