"To me, burn out is a result of feeling like you're not getting anywhere, and that just plain isn't the case at a company where we consistently ship things with huge scopes, on time and to resounding success."

Just because a company is getting somewhere, doesn't mean you or your team or even your org is. You mustn't overgeneralize your own positive experiences at the company to reflect that of a majority of people working there. (Of course, for people with the opposite experience, overgeneralization should be avoided as well.)

It's a big company. Experiences will vary.