I remember the same discussions when 29'ers were becoming a thing...

After not riding a MTB for a looong time - coming from an old school Rockhopper and then jumping on to a modern full squish 29'er - WOW - worlds of difference. While each small level of change that happened in between may have seemed like marketing or hype - the bikes have actually improved drastically. Especially when compared to the evolution of road bikes.

Maybe the brands have reached the limits of what they can do on a 29 platform, and this is just the next step.