IMO, Lexus has profited very well from using simple cheap FWD-based underpinnings for their top selling RX/NX/UX's.
Likewise, using Camry FWD-based platform as underpinnings for ES has brought Lexus considerable profits from high sales with very low cost Camry FWD-based underpinnings.
That's why Toyota Motor Corp is the wealthiest car manufacturer in the world with net equity of some US$200 billion, when Daimler AG only has US$70 billion - Spwolf loves it when I say nice things about TMC.
In the United States, because Lexus has two luxury cars of similar exterior size in the ES and GS, the ES obviously steals sales from the GS just like an E Class/5 Series/A6 steal sales from the CLS/6 Series/A7 4 door coupes - thus,
I don't really believe that there is a sales problem with GS.
The only thing I acknowledge is that the current 2012-19 4GS sales has suffered sales in the US probably for a number of reasons, with peak sales on its debut year down to 22k/year, where 3GS sold 33k/year, and 2GS also debut with over 30k/year.
For those who think that 4GS sales fell due to SUV's, this is not true, because from 2002-09 to 2009-16 period, the E Class's peak sales increased from 50k/yr to 69k/year!
Likewise, from 2003-10 to 2010-17, the 5 Series increased its peak sales from 56k/year to 60k/year.
Thus, in the same period of time, only 4GS's peak fell backwards, and fell backwards significantly too - from 3GS's 33k/year to 4GS's 22k/year.
As for the Toyota Mark II.
The Mark II actually started life out as the Toyota Corona Mark II; an upmarket version of the Toyota Corona.
Later, the Toyota Mark II became its own with the numerous sales channels in Japan selling the Toyota Cresta luxury variant and Toyota Chaser sports variant.
When the Toyota Mark II reached its tenth generation, it was called the Toyota Mark X [Ten].
The Nissan Maxima also started life out as the Nissan Bluebird-Maxima, before it became the Nissan Maxima itself.
The Mark II was supposed to be sub-4.7 m long and sub-1.70 m wide to be under the Japanese Passenger Size Vehicle tax limit.
By 1989, the Japanese government abolished the 4.7 x 1.7 m Passenger Vehicle tax limit to make their vehicles more internationally competitive.
Some time in the 1990's, the Toyota Mark II shared the Toyota N Platform with the Toyota Crown/Aristo/GS, and later sharing with the compact Altezza/IS too.
As such, the Toyota Mark Series falls "
half-way" in size between the compact Altezza/IS and the midsize Crown/Aristo/GS; the Toyota Mark Series is neither genuinely compact like C Class, but it is not genuinely midsize like E Class either.
We could sell an intermediate size luxury RWD car in the US, but it would be in no man's land, but more importantly, US consumers would probably complain that a Toyota Mark X-based ES with an intermediate size is
too cramped inside - because back in the 1980's, this is how many consumers complained about the Toyota Cressida [Cressida was the export name for the domestic Mark II], and its sporty competitor the Nissan Skyline.
In Japan, the Toyota Mark X sales are becoming diminutive, probably because most people either adopt more genuine compact IS, or more genuine midsize like Crown/GS.
That's my 2 cents...