The game will evolve, though, as everything does - unless it's pretty much scrapped altogether, as Invictus hinted at (which is an intriguing and, in my opinion, not unrealistic prospect).
It's almost unthinkable to me that football will go on developing, changing, step by step (some more dramatic than others), over the coming decades - but without the emergence of a new player people will put on a pedestal at the time, and practically deify once he hangs up his boots (or whatever they'll wear in the future). It's happened at every stage so far, so unless there suddenly are no more stages, it will happen again.
It doesn't take someone using the ball better than Messi in the sense you imply: Messi isn't superior to Maradona, Pelé or Di Stefano in every aspect of his game - yet many people (who actually concede this) still consider him the greatest ever. That's one thing (and I know this wasn't your point). But more importantly, a shift in the game, a development, could easily see the emergence of a new way of using the ball. Which will make Messi's way of using the ball appear in a different light. The fanbois of the future will then simply argue that Messi's way wouldn't work in the modern game - and bang, he's out.
One pretty obvious predict-the-future point: In X years we could be looking at a game that has evolved beyond the current state in purely physical terms: This has happened throughout football history - there's always a way to speed things up a wee bit more, beef things up a wee bit more, make boots and footballs a wee bit lighter, or whatever the case may be...and before you know it, a new phase has been entered. People will go back to Messi's highlight reels and comment on how this or that has changed, and those who need it, will find plenty to support the argument that this or that is outdated and has been improved upon.
