If resolution was the only metric, that makes sense.
But reality is that we're seeing higher color depth ("HDR"), higher framerates, higher quality sound streams (e.g. Dolby Atmos and beyond), and even technologies we aren't envisioning today because the hardware isn't "there" yet.
If 8K is only a resolution bump, then boring, but it may be much more than that. 4K is.
Shoting on lower resolution gives you better color depth/accuracy AND higher framerates to chose from.
It gives better color because (all other things being the same) signal and color accuracy degrade with higher resolution -- less photons "hit" each diode on the sensor.
And there's literally no digital cinema or amateur camera that doesn't allow for much higher framerates in lower resolutions than it does on higher resolutions. That's because the higher the resolution the more taxing it is for the sensor and processor in the camera to keep up with high frame rates. 4K x N fps means 4 times more volume than 1080p x N fps.
Lastly, sound is totally orthogonal, because that's recorded off camera with special recorders.
So we might be getting better color depth and sound quality lately, but that's not because we moved to higher resolution.
But reality is that we're seeing higher color depth ("HDR"), higher framerates, higher quality sound streams (e.g. Dolby Atmos and beyond), and even technologies we aren't envisioning today because the hardware isn't "there" yet.
If 8K is only a resolution bump, then boring, but it may be much more than that. 4K is.