It is all very well saying throw away homeplugs and install cat5 or 6 but not everyone has that capability. There is no way my wife would allow me to cable up the house with cat5 and even if she did the cables would all have to run round the outside of the property with holes through walls to provide access indoors. Sometimes you just have to live with what is permissible.
Stuart
wireless has hit the point its "good enough" for mainstream use, AC is faster than most homeplugs out there, and N is good enough for things like super hd netflix (I know as I watch netflix on my wii-u which is N 2.4ghz single band in a congested area).
In terms of wiring where there is a will there is a way, in one of my old places to live back in 2000 when wireless was in its infancy and no such thing as homeplugs we drilled holes in the wall and had cables going down side of house, wasnt a big deal, probably 1-2 hours work. There is also the option of putting under carpets etc.
Whilst I acccept there may be certian homeplugs and certian situations they work ok, the problem is a significant amount dont, and unless everyone checks (which I doubt they do) then these will be a cause of interference.