What is your source of info for this? Do you have data on all DI Nissans, or just ones that started running rough after 75K?
Again, Is your source data a good random cross section of all Maximas or might it be biased towards ones that developed some fault or other?
I don't see why the milage between failures should be consistent between different systems. Either it's coincidence or some common component is being used (and needs beefing up).
Like with everything, you'll only hear about the ones that fail. It's not news when something works. Otherwise, newsgroups like this would be deluged with posts along the lines of "100K miles and the height adjuster on the driver's seat still works like new"
I'm sure that's one reason why this system gets such a bad press. When it fails, it more often than not dumps you at the side of the road, in the middle of nowhere, without warning. Then it costs loads to get fixed. Behavior like that will make absolutely sure that news of the breakdown gets spread far and wide. There's nothing that all the perfectly working systems in the world can do to balance this out.
Cheers,
Colin.