YMMV, but I've never done anything worthwhile without going through a difficult period near the end. It's just the nature of the beast, and it was as true on Windows NT as on Quake.
I never said anything about death marches, or at least I don't think I did. I worked hard and steadily throughout Quake, and John worked incredibly hard and steadily always, but that didn't change significantly toward the end. It's just more difficult at the end, because fixing bugs and improving performance and putting in less interesting features (like menus) isn't as much fun as experimenting with new renderers, because there's pressure to get it exactly right, and because you've just seen too much of the same game for too long. It's not hellish or life-destroying, it's just hard. I know some very talented people who just aren't willing to push themselves through it, and that's their right, but they also don't get finished projects out the door, and in the end, that's what it's all about.
As for companies that routinely put their people through death marches - I have nothing good to say about that. John and I volunteered to do what it took to ship Quake. It makes a huge difference when it's internally motivated rather than demanded by management.