The South actually lost less men at Gettysburg than the North. There are various numbers, some saying different but the best sources say so.
After the first or second year the South was outnumbered in every way, often by huge numbers such as supplies. The only thing the South had an advantage was their gunpowder was better.
Interior lines as well.
If the Union had adopted Winfield Scott's "Anaconda Plan" at the beginning rather than a year+ later, the war would have been quicker and much less bloody! If Scott wasn't 74, aged and ailing, he might have been able to push this plan. Alt-history is always a fun mind game!