The increase in frequency reduces signal penetration. Things like walls become major sources of signal attenuation. In open office plans, with no obstructive walls, no problem. In a house or apartment where you're separated by multiple walls (and the materials/thickness those walls are made of) that can add up to significant signal loss.

I haven't personally tried any 6GHz wifi technologies. Have you used it in any places where you're separated by obstructions from the access point?