Easy. You just have to break down his abilities and see if someone can do better in that category.
Finishing: Top tier, could do better with his weak foot and long range shots.
Passing: Top tier. From long range to through balls to one-two's, don't see how anyone can improve on his abilities here.
Dribbling: Again hard to see anyone do better than him. As good? Yes. Better? Highly unlikely.
Aerial ability: Average. Someone taller can easily surpass him here.
Balance: It's hard to think of anyone close to him in this regard, this trait is (IMO) extremely important, it means he can change directions at the speed in which he does it, the ability to ride tackles, withstand defenders pressure, even the way he controls the ball at speed. Anyone that can match him here is almost guaranteed to be short in stature, which virtually translates to average aerial ability.
Agility/Speed: Messi's sprint speed or 'top speed' although good, isn't anything special. Where he excels is in his ability to go from 0-60 extremely quickly and his speed with the ball at his feet. The former is invaluable when you're going past a defender, whilst the latter is key to maintaining your distance advantage afterwards. These two combined is why it seems so easy for him to run past defenders and score goals. At best anyone who wants to challenge him here will be hoping to match him. Ronaldo is faster, Bale is faster, Aubamayang is faster, but Messi is just more effective.
So just looking at a few categories, you can see that he has his weaknesses which others can match or surpass. What it all boils down to is first of all, how many people can match his strengths, second, how many of those people will be lucky enough to have prolonged careers to show their ability, out of these players, how many will go out and consistently put out performances at Messi's simply unmatched rate? Even then, will they have the mental ability to show up at the biggest games?
Let's say they do.
Now it's time for them to succeed the way he has, the trophies, the individual awards, the value he brings to football fans. To break or match the records he's set.
His records are long and impressive but this graphic here puts in perspective the sheer magnitude of Messi's impact in football.
Is it possible? Messi is living proof of it.