To be fair, the South was facing impossible odds. Their only hope was that the North would let them go. Lee's delusion was that annihilating the Army of the Potomac would achieve that goal. It's what compelled him to wait an extra day in Sharpsburg after the bloody events along Antietam Creek in hopes McClellan would attack him in place. (Which goes to show that even as late as September 1862, Lee didn't really understand McClellan.) It's what caused him to engage in the Battle of Gettysburg. If Lee had avoided battle whenever possible and simply led the Army of Northern Virginia in large scale foraging raids through the North, he could have both devastated Union morale and preserved his strength.
For Lee to have won the war using the strategy he followed, he would have had to face an opponent as reckless as John Bell Hood.
Many revolutions have succeeded against impossible odds at the same time. This gets back to the point that I was making about how the Lost Cause has warped the view of Grant and Lee as well. By putting down Grant's accomplishments (particularly out west) and glossing over Lee's mistakes, they were able to deify Lee at Grant's expense.
It also doesn't help that Grant's Presidency was marred by corruption and so forth, which further harms his reputation as this chain cigar smoking drunk.
