What this means for the GS in the States? We sill don't know. But we do know that the ES moved 51,398 units here last year, compared to GS sales of 7,773. Those numbers represent double-digit declines compared to 2016, when the sold ES sold 51,398 units and the GS sold 14,878. In August 2017, spy photographers caught the 2019 ES testing with the Audi A6 and Mercedes-Benz E-Class, hinting the coming ES has grander aspirations than being a florid Toyota Avalon. That still wouldn't make the ES a pure replacement for a sporty rear-drive sedan, but are there enough GS buyers for Lexus to care?
Last October, Car and Driver reported that Toyota's Gazoo Racing brand was working on a new GS F, but C/D couldn't tell if Gazoo meant a new model or the current one. Last June, Lexus Australia head Peter McGregor refuted the death of the GS. When asked if dealers were interested in both the ES and GS, McGregor responded, "I think what dealers like is a full line-up... that meets the market requirement in every key segment." Making clear that he couldn't speak on future product, McGregor also commented, "I think [a new GS] would still be a four-door sedan in terms of its application, but the exterior styling may appear to be more liftback." The third-gen GS struck a fastback profile, and you could see the new LS as a modern evolution of that old GS design.
A member at the Lexus Enthusiast fan forum has found that the the next GS, internally codenamed 300B, still shows up in industry databases alongside the date "SOP [Start of Production] Q2 2019." Throwing money at an updated GS F wouldn't make sense for a doomed sedan. Could the GS reappear as a four-door coupe? Certainly, if for no other reason than that Lexus needs something to fill the slot between the $38,950 ES and the $75,000 LS.
Perhaps a new GS would go even further with the design language revealed in the LF-FC concept; Toyota's head of advanced design told Automotive News last year, "At a certain point of time, the traditional, square, three-box sedan will go away." Clarity might be a while in coming, but we should know something by the end of the year.