Problem isn't just the distance - it's the amount of effort and the specific types of travel to Tokyo for work - we almost always stay in Shinjuku for business reasons - if we're traveling in a group and flying from Narita, everyone wants to go early to avoid "missing a train or being delayed" which is natural if they haven't done it before. Because the main flights from narita to Seattle all happen in the late afternoon, then we have to set off in a big clump. If we were staying near Tokyo station it wouldn't be so bad, but it would still be a production. Whereas with Haneda, we can just chill and have brunch, do some shopping, then hop in a car or multiple cars in a civilized fashion with no trains or station switching. And no responsibility for the other travelers who're nervous about negotiating the trains to the airport.
If I were on my own and in charge of my own destiny I'd be much more relaxed about grabbing a later NEX, but it's still a long trip. I've also found that my colleagues and traveling companions think they're in Tokyo as soon as the fields give way to city. You can see them thinking that surely we must be pulling into the city any moment now....
To be fair the NEX is a pleasant, relaxing ride that puts you right at your terminal, but again, when you're there for business, that whole morning of shopping or eating is at a premium compared to leisure travel. And of course you get about a half day messing around when you arrive at narita, getting bags, train tickets and so on.
Oh and one other weird thing - for some reason the equipment to Narita is more likely to be a Dreamliner or a380 and that makes a HUGE difference on a flight that long. Anyhoo I'm being pretty granular and anal here.