Lee also ordered the disastrous Pickett's charge, a futile slaughter of his men. He was not facing Grant until the end, and Grant made a quick end of him.
Had Gettysburg and Antietam not happened, Britian and France would have recognized the Confederacy, McClellan probably would have defeated Lincoln and negotiated a truce. By the time Grant arrived on the scene, the southern population was hoping for a quick end; they were already defeated, it was just a matter of when and where Lee surrendered. Stonewall Jackson's death was also a huge blow as was Sherman's "march to the sea." Lee had no real supply line from 1864 onward, he COULDN'T win a battle of attrition. I truly believe that had Lee faced Grant early in the war, he would have defeated him just as he did with McClellan.