That is to say, for something of no artistic worth whatsoever, which future generations will ignore- just as we ignore the memorial statues on all the other plinths.
Because it's almost inconceivable that a real artist would be handed a commission like this, isn't it?
Or would want to undertake it.
It's not just that public expectations will restrict the artist to the bland and generic- though it's that too- it's also that the genre "dead hero on horseback" is completely moribund. For all the implicit drama, there's surprisingly little you can do with it. A horse is a horse is a horse- and there's not much variation you can work in the rider's pose either: the legs can only go so, the back must be straight, at least one arm must be holding the reins.
The problem was solved- back in the 1480s- by Andrea Del Verrocchio. His Colleoni monument (I'd post a picture, but I can't find a decent one online) is the genre's definitive masterpiece. Everything since restates or copies Verrochio- and suffers by comparison.