He’s already 31 years old. The maximum he will get will be around ~6k Test runs, that’s if his form returns and he works on his many deficiencies. For ODI, I think 8k will be a realistic target for him. For T20, 6k will be the target. ~20k international runs across formats is not a bad stats for any player, but for a player of his caliber and hype, it’s a massive disappointment and it all boils down to his rigidity and inability to improve his game. He’s either struggling or is dropped and doing instagram modeling instead of playing red ball cricket and working out his deficiencies.
It’s also the story of Pakistan: inability to grow and fix mistakes.