For most of the history of video games, every 5-10 years or so, computing power had advanced enough that if you made a new console with the latest tech, games made for that new console would be just demonstrably better-looking than the previous generation in every respect.
The Magnavox Odyssey could only generate a small number of white pixels on an otherwise black screen, and you needed to put colored sheets over the TV to turn them into a playable game. Compared to that, the Atari 2600 was a huge leap forward - look! Multiple display colors! No need to slap weird sheets to the TV screen! It just works on its own! Anyone can see this is better!
Then came the jump to the NES era, and now the pixels were smaller, the color variation higher, the complexity climbed. Anybody could see this was better.
Then we had the SNES era, and now there were even more color options and even smaller pixels, while allowing way more sprites on screen at the same time, killing the problem of sprite flickering if too much happened at once. Anybody could see this was better.
Then was the Playstation/N64 era, and games could finally be rendered in full 3D natively without add-on workarounds. It was blocky and full of polygon jitter, but it worked and worked beautifully. Anybody could see this was better.
Then came the PS2, Xbox, and Gamecube era, and the 3d models could be rendered in much higher fidelity. More things on screen at the same time, higher resolution textures, anybody could see this was better.
Then we hit the PS3, the Xbox 360, and the Nintendo Wii. Even crisper graphics were possible with higher-fidelity models and more involved animations. If you looked at it for a bit, anybody could see this was better.
If you looked at it for a bit.
It had finally stopped being immediately obvious.
When the eighth console generation - PS4, Wii U, and Xbox One - hit shelves, graphics were continuing to be pushed. There were forty years of momentum behind the push for higher-fidelity graphics, because each new generation created the opportunity for shinier graphics that easily and obviously pushed the new console above and beyond what was already out on the market. So of course, that's what the big console manufacturers advertised. Shinier graphics, better looks, fancier models, higher fidelity, and yeah, if you looked at it for long enough, you could see how this one looked more realistic.
But did it look... better?
We're now fifty years into video game consoles being a thing. Entire careers began, grew, and came to an end with a comfy retirement, within a culture of always pushing for better shinier graphics, because that's what the public wants, right?
With the ninth console generation, it stopped being obvious. A trained eye can tell the difference, sure. And even a layman can tell something's changed if they have enough time to look. But it's no longer the obvious, self-evident improvement it once was that separated console generations. And as new people continue entering the industry, and are trained by people trained by people who spent their entire careers correctly pushing for higher-fidelity graphics every step of the way, that old reliable train is finally running out of track.
But the old guard keeps on shoveling coal into the furnace, because it's been fifty years with more track always in sight, fifty years where the train can keep running forward, why bother even pulling on the brake lever anyway?
... hey which lever was the brake again?