He lost a lot of the good ones: Albert Sydney Johnston at Shiloh, Barnard Bee at Bull Run, Jackson at Chancellorsville, JEB Stuart at Yellow Tavern ...
Irreplaceable talent.
Grant was not a sophisticated opponent. It isn’t hard to fight a man that comes at you head on. Not much strategy in a forced war of attrition. Like the move Wales, Grant not a hard general to understand. He leaves his own dead and crushed army wherever he goes.