If the rumour of the cancellation of future V8 engines is true, it is just an admission that there is no longer a demand for large, V8 engines, especially coming from Japanese automakers. There is certainly no demand in Japan, no demand in China, no demand in East and South Asia, and very little demand in North America, all major markets for Lexus.
The only area where there is still a demand for the V8 is Europe but that is being met by the European automakers; no other automakers are able to sell V8-engined vehicles in Europe.
Enthusiasts in this internet forum (largely in the USA) want a Japanese-German hybrid, a German luxury sports sedan with a roaring V8 that possesses insane horsepower levels and accelerates lightning-quick, but is built with Japanese attention to detail and built to Japanese levels of reliability. Yet no other luxury vehicle buyer is looking for this type of vehicle. So the insane-horsepower-roaring-V8 luxury sports sedan is a infinitesimally-small niche that most automakers can no longer afford to compete in; the European automakers can because they still have a demand for these vehicles in their home market and the numbers they export to North America are just incremental numbers. With no demand for V8 sedans in its home (and other large markets), the Japanese (and soon the Korean automakers and even the American automakers also, I believe), can no longer afford to produce V8-powered sedans.
Enthusiasts have refused to accept this business decision. Enthusiasts are not a large enough group of buyers to demand what they want and sway this business decision.
I see your point and agree with much of your sentiment, but you have to ask yourself at what point the demand for V8 Lexus models fell by the wayside. For twenty years, Lexus built some of the most desirable and class leading V8s in the industry. The GS 400 was once the fastest sedan in the world. LS 400 and LS 430 were some of the fastest and most fuel efficient V8s in their segments, same for the SC430. Even in 2007, the LS 460 rivaled the S550 with horsepower and performance, but in a more efficient package. The IS F was just as good or better than the M3, C63 and RS4, and is still one of the most desirable performance vehicles you can find in the aftermarket commanding prices of $30k or more, even ten years later.
But around 2010, all of that changed and Lexus gave up, both with higher performance engines and new expanding segments. As Lexus' V8s have fallen stale, people shopping for those cars have gone elsewhere for Mercedes, BMW, Audi, AMG, RS, M, PHEVs, EVs, four door coupes, four door coupe SUVs and much more. As powertrain technology has advanced, I think the case for a V8 has gotten smaller (so I agree with you there), but a few months ago, Lexus stated that their vehicles over $90k would be V8s. Real world, loyal LS buyers haven't been buying the LS 500 because it doesn't have one. Lexus showed the LC F to dealers two years ago, said the car would launch soon, and then it miraculously got pushed back and then cancelled. Now V8s cancelled.
The bigger problem here isn't just about no V8s, it's more that there's nothing to make up for them. The disappointment would be significantly less if we had higher performance hybrids, which would be an amazing competitive advantage for Lexus, or electric vehicles. So it's not that we don't just have new V8s, it's that we don't have any sort of "Lexus performance" in any form - after the F program was launched and hyped just about a decade ago, LC F teasers, comments from Lexus execs about new turbo V8s, the list goes on.
Lexus hasn't kept up with their own legacy of best-in-class V8s, nor have they kept up at all with similar competitors (BMW, Mercedes), electric competitors (Tesla) or high performance hybrids (Porsche). So what are we supposed to feel good about right now, aside from the LC?