Well, considering that the final design was set about 31 months ago, it's not shocking in the least it "stayed true to the concept".
Wasn't really a concept honestly, because everything was locked in 2 years ago and the showcase of "Z Proto" was to give an early reveal, after such a long wait (12 years). Once it's locked in, you can't make any more changes to the sheetmetal (at least until a mid-cycle update).
This ended up costing a quarter of a billion dollars, versus 4x to 8x that amount, to support an all-new RWD modular unibody architecture, which was an absolute non-starter where Infiniti was concerned. Ghosn approved this car as chairman (not CEO), before his arrest some 10 weeks later. RWD ICE Infiniti is just not likely going forward, so this being all-new wasn't going to work by itself.
It would be $100k to be an all-new car, an all new architecture. As January 2018, a new Z was cancelled.
Some of us (myself and 2 others) had mentioned back in the spring of 2018 that a fully 100% new car was dead and then by summer, it would be "heavily facelifted" on the same basis instead for MY 2021 (got delayed after September 2018) at a few hundred million. This is it pretty much, as anything after this is not ICE, just like the 2029 Mustang.
I didn't say much in terms of my annoyance towards and skepticism over "400Z" the last 3 years, but I don't know where the British media got "400Z" and why the rest of the idiotically obtuse media and social media hoes decided to automatically jump on that bandwagon, without verifying it to be credible. One or two places had the audacity to even claim, "400Z" had been trademarked by Nissan. Their proof was a "Z" insignia/logo and nothing else. They pretty much lied.
Knowing Nissan very well due to former business and also the patenting/trademarking process, that absolutely isn't how it works LOL. I checked globally and in comparing some in progress patents of mine (association w/employment, not sole inventor) to existing trademark filings, there's no existence of "400Z" in any trademark database nor internally has that ever been referred to. Seeing this car in 2019 (not yet in metal), it wasn't called that either back then. Regarding the VR30DETT 3.0L TT V6 for Infiniti, it presented a problem back in 2012. In 2011 or 2012, Nissan had filed several trademarks for 2014 G range. In addition to the trademarks "G37" and "G25" first filed in the mid-2000s (circa 2009 for "G25"), new trademarks of "G22d", "G30t", and "G35h" were filed in 2011-12 for the current car.
When Johan de Nysschen became head of Infiniti, months later by the fall of 2012, he quietly ordered a whole redo of the brand nomenclature to Q/QX to accommodate a perceived "downgrade" by ignorant consumers with G30t or M30t (3.0L TTV6) vs G37 & M37 (VQ37) or M56 (5.6L VK56 V8). Plus, reorganize it to something that resembled his time at Audi (A, S, R/RS, and Q).
Infiniti Renaming was announced in mid-December 2012, 3 weeks before the 2014 Q50 was unveiled and several months before 2014 models went on sale. Q50 was designed as the 3rd generation G37 from the onset and never was a Q50 during development.
When it came to Z, it was a similar story with 370Z vs 300Z, so dropping the displacement nomenclature makes sense. As you already know, trademarks have to be secured well before production starts. No 400Z trademarks exist, yet I seeing and hearing how a lot of YouTubers, are calling it "400Z" just for extra clicks and to drive traffic to them.
i-Force Max in example was filed well in advance of Tundra hybrid launch in early 2022. Same applies to most Nissan vehicles and pretty much most companies. Once you start formalizing a vehicle development program, after setting a final design, package plan, and defined set of parameters, marketing and management determine nomenclature/nameplate and file trademarks via their legal team some 2 to 2.5 years ahead. At latest, it's 1 year before launch (see IS 500). What I have seen here, is them take liberty with their reporting and behave lazily.
A lot of car news sites often take everything out of context or create their own muddled narratives, which the next person takes to be (wrongfully) accurate. There are days I just want to turn my brain off and when I read obviously misleading stuff, I become annoyed, because that neuro-vacation ends almost immediately and I have to start second guessing what I read and do their homework.
They need to separate opinion pieces from simply reporting the facts on what's here now and what's coming down the road. This whole attempting to be a cut-rate Jay Leno or Jeremy Clarkson, gets tiring when many of them use that to report info and often get it wrong LOL.
If I wasn't such a busy person nowadays and invested in my professional work (and personal life), I would start a media company and encyclopedia that is all about informativeness and dead on accuracy regarding automobiles, not always being first. Between Wikipedia, YouTubers/social media, and questionable news reporting, it's a clusterfuck of proportions and the rest of us have to play cleanup with their mistakes (ranging from minor to glaring).